A European update on transcatheter aortic valve implantation (TAVI) in the COVID era

Minimally invasive approaches for aortic valve replacement are now at the forefront of pathological aortic valve treatment. New trials show comparability of these devices to existing therapies, not only in high-risk surgical cohorts but also in low-risk and intermediate-risk cohorts. This review provides vital clinical and anatomical background to aortic valvular disease treatment guidelines, while also providing an update on transcatheter aortic valve implantation (TAVI) devices in Europe, their interventional trials and associated complications.

Regulation of human cortical interneuron development by the chromatin remodeling protein CHD2

Mutations in the chromodomain helicase DNA binding protein 2 (CHD2) gene are associated with neurodevelopmental disorders. However, mechanisms by which CHD2 regulates human brain development remain largely uncharacterized. Here, we used a human embryonic stem cell model of cortical interneuron (hcIN) development to elucidate its roles in this process. We identified genome-wide CHD2 binding profiles during hcIN differentiation, defining direct CHD2 targets related to neurogenesis in hcIN progenitors and to neuronal function in hcINs. CHD2 bound sites were frequently coenriched with histone H3 lysine 27 acetylation (H3K27ac) and associated with high gene expression, indicating roles for CHD2 in promoting gene expression during hcIN development. Binding sites for different classes of transcription factors were enriched at CHD2 bound regions during differentiation, suggesting transcription factors that may cooperatively regulate stage-specific gene expression with CHD2. We also demonstrated that CHD2 haploinsufficiency altered CHD2 and H3K27ac coenrichment on chromatin and expression of associated genes, decreasing acetylation and expression of cell cycle genes while increasing acetylation and expression of neuronal genes, to cause precocious differentiation. Together, these data describe CHD2 direct targets and mechanisms by which CHD2 prevents precocious hcIN differentiation, which are likely to be disrupted by pathogenic CHD2 mutation to cause neurodevelopmental disorders.

A novel case of lupus nephritis and mixed connective tissue disorder in a COVID-19 patient

Introduction

Mixed connective tissue disease (MCTD) is a rare autoimmune condition characterized by Scleroderma, Polymyositis, and Systemic Lupus Erythematous (SLE). Though a possible relationship between COVID-19 and autoimmune diseases has been recently reported, its pathophysiological mechanism behind flares in Lupus Nephritis (LN), a complication of SLE, remains unknown.

Case presentation

A 22-year-old COVID-19 positive female presented with anemia, bilateral pitting edema, periorbital swelling, and posterior cervical lymphadenitis. Further inspection revealed lower abdominal striae, hepatosplenomegaly, and hyperpigmented skin nodules. Complete blood counts showed elevated inflammatory markers and excessively high protein creatinine ratio. Antinuclear antibody titers were elevated (anti-smith and U1 small nuclear ribonucleoprotein) and Rheumatoid Factor was positive. She was diagnosed with MCTD associated with a flare of LN. To control her lupus flare, a lower dose of steroids was initially administered, in addition to oral hydroxychloroquine and intravenous cyclophosphamide. Her condition steadily improved and was discharged on oral steroid maintenance medication.

Discussion

We present a rare phenomenon of newly diagnosed LN, a complication of SLE, with MCTD in a PCR-confirmed COVID-19 patient. The diagnostic conundrum and treatment hurdles should be carefully addressed when patients present with lupus and COVID-19 pneumonia, with further exploration of the immuno-pathophysiology of COVID-19 infection in multi-systemic organ dysfunction in autoimmune disorders.

Conclusion

In COVID-19 patients with LN and acute renal injury, it is critical to promptly and cautiously treat symptomatic flares associated with autoimmune disorders such as SLE and MCTD that may have gone unnoticed to prevent morbidity from an additional respiratory infection.

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SLE disease has been associated with COVID-19. However, there is a lack of data on LN in conjunction with MCTD in COVID-19 positive patients.

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A possible relationship between Coronavirus disease 2019 (COVID-19) and autoimmune disease has been documented in many case reports.

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Because of the overlapping clinical manifestations and laboratory findings between lupus and COVID-19 pneumonia, the diagnostic problems and treatment hurdles should be carefully addressed.

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In COVID-19 patients with LN flare and acute renal injury, it is critical to resolve any reversible causes of the kidney injury and manage the COVID-19 before treating the LN.

Abstract 2007: Investigating how RIPK1-mediated mitophagy induces cell death in ECM-detached cancer cells

Lead Contact Metastasis is responsible for 90% of deaths caused by cancer. For cancer cells to begin successful metastasis, they must detach from their extracellular matrix (ECM) and evade intrinsic cell death mechanisms. Detachment from the ECM is known to induce a caspase-dependent cell death program, termed anoikis, that cancer cells have been shown to circumvent. Nonetheless, overcoming caspase-dependent cell death alone is not sufficient to promote survival during ECM-detachment, but cancer cells must also address caspase-independent cell death programs. In our recent studies, we have identified RIPK1 as a critical mediator of ECM-detachment induced caspase-independent cell death via its capacity to promote mitophagy and subsequent accumulation of mitochondrial ROS. More recently, we have begun to examine how ROS levels are elevated as a consequence of mitophagy and how these ROS ultimately promote cell death. During mitophagy, autophagosomes containing mitochondria fuse with lysosomes containing a plethora of hydrolases that could facilitate cell death. As such, we sought to examine the relationship between RIPK1-mediated mitophagy and lysosomal membrane permeabilization (LMP) Using immunoblotting, we found that not only does ECM-detachment promote the expression of the lysosomal protease cathepsin B, but also that this induction is dependent upon RIPK1 activity. Given that mitochondrial ROS (mitoROS) was shown to be a consequence of RIPK1-mediated mitophagy during ECM-detachment, we investigated if mitoROS were required for the observed changes in cathepsin B expression. Indeed, when treated with a mitochondrial ROS (mitoROS) scavenger, cathepsin B protein levels noticeably reduce. Taken together, this data suggests that RIPK1-driven mitoROS production is playing a role in regulating cathepsin B expression during ECM-detachment. Future studies will be aimed at determining whether these RIPK1-mediated alterations in cathepsin B are linked to the induction of caspase-independent cell death.

Citation Format: Jordan Alexandria Cockfield, Ishan Antony, Samantha Ekanayake, Zachary T. Schafer. Investigating how RIPK1-mediated mitophagy induces cell death in ECM-detached cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2007.

An Outlook on the Impact of HIV Infection and Highly Active Antiretroviral Therapy on the Cardiovascular System - A Review

HIV has been related to various cardiovascular pathologies in both adults and children. Highly active antiretroviral therapy (HAART) has been effective in subduing viral replication and improving immunity thereby reducing the effects of HIV both in AIDS and other chronic diseases related to the virus. Complications related to HAART have been reported with metabolic disorders and cardiac effects seen based on the therapy. HIV and HAART have shown to have direct effects on the cardiovascular system, and more public awareness and medical knowledge are required on this subject. This literature review tries to shed some light on the role of HIV and HAART in the cardiovascular manifestations seen in HIV-infected individuals.

Neuroplasticity Improves Bipolar Disorder: A Review

Bipolar disorder (BD) is known for impairments in neurotrophic and neuroprotective processes, which translate into emotional and cognitive deficits affecting various brain regions. Using its neuroplastic properties, lithium, thus far, is the mood stabilizer used to amend the pathophysiological imbalance in BD. Neuroplasticity has gained massive popularity in the research department in the past decade, yet it lacks direct effort in changing the protocol through which physicians treat BD. Physical activity alongside cognitive therapy is theorized to produce long-term changes in the executive control network due to the assimilation of new neurons, amendment of emotional lability through hippocampal neurogenesis, and strengthening the stability of frontosubcortical and prefrontolimbic brain regions via neurogenesis. This review aims to provide an incentive for utilizing neuroplastic mechanisms concerning impairments dispensed by BD.

Cardiovascular Involvement in Psoriasis, Diagnosing Subclinical Atherosclerosis, Effects of Biological and Non-Biological Therapy: A Literature Review

Psoriasis is a long-lasting, noncontagious chronic inflammatory disease of skin and joints. Previous epidemiological studies have demonstrated that psoriatic patients have a shorter life expectancy, mainly due to cardiovascular (CV) events with a higher prevalence of cardiovascular risk factors like dyslipidemia, diabetes mellitus, insulin resistance, obesity, and hypertension. Besides these risk factors, psoriasis likely plays an independent role in increasing CV events probably due to the chronic inflammatory state. This literature review aims to summarize the mechanism of atherosclerosis formation, CV risk factors, tools to diagnose subclinical atherosclerosis, and the effects of various therapies in psoriatic patients to prevent cardiovascular-related deaths in psoriasis. This review was performed by searching the relevant articles in PubMed and Google Scholar databases without including any exclusion criteria and time limitations. Our review documented that psoriatic patients are at increased risk of CV events due to chronic inflammatory profile and the associated CV risk factors. Also, anti-inflammatory therapies may prevent early subclinical atherosclerotic vascular changes reducing cardiovascular events. However, the available studies lack to establish the exact targets for CV risk factors, to assess the clinical importance of screening for subclinical vascular changes and the impact of anti-inflammatory therapies on CV risk profile in psoriatic patients. This heightened awareness about the CV involvement in psoriasis should encourage conducting large, well planned comprehensive studies to address these issues that can reduce cardiovascular morbidity and mortality.

Transdermal Nicotine as a Treatment Option for Ulcerative Colitis: A Review

Ulcerative colitis (UC) is primarily a disease of non-smokers or ex-smokers. Since there have been previous claims of the beneficial effects of transdermal nicotine, researchers studied its efficacy to include it in the treatment regimen: to prevent remissions and as maintenance therapy. This review aims to evaluate the efficacy of transdermal nicotine as a treatment option for mild to moderately active ulcerative colitis. We shortlisted 22 articles after a careful analysis and elimination process. These articles were reviewed and analyzed, and it was found that transdermal nicotine in combination with conventional therapy was more beneficial than individual treatment with either. Further controlled studies evaluating the appropriate dosage for remission and maintenance treatment needs to be done.

Role of Cannabis in the Incidence of Myocardial Infarction: A Review

Legalizing cannabis use in various states in the United States has caused increased substance abuse, mostly among young people. There are very little data focussing on marijuana use and myocardial infarction (MI) incidence. The objective of the study is to analyze the published papers for cannabis-induced MI and derive a strong relation between cannabis use and MI and understand the pathophysiology. An online search was conducted in PubMed, Google Scholar, and PubMed Central to find relevant publications examining patients who developed MI due to cannabis use. Out of 32 articles that were identified for this review, 17 are case reports, one is a letter to the editor, eight are observational studies, and six are review articles. Many studies have proposed different mechanisms by which cannabis affects the body. Our study shows that marijuana can precipitate MI even if it is used for the first time. Limited data is available to comment on the mortality of patients after cannabis-induced MI. These findings highlight the necessity for public awareness to prevent the ill-effects of cannabis, especially for teenagers and older people.

Left ventricular mechanical efficiency in hypertensive patients with and without increased myocardial mass and with normal pump function

Left ventricular hypertrophy (LVH) is a physiologic process of adaptation of the heart to mechanical load increase. Despite depression of left ventricular contractile performance, mechanical efficiency and ventriculoarterial coupling are preserved in hypertensive patients with LVH. To assess the differences between patients with and without LVH, left ventricular contractile performance and the ventriculoarterial coupling were compared in two groups of hypertensive patients with similar body surface area and arterial pressures, and normal pump function: 30 patients with LVH (group 1) and 23 without LVH (group 2). Left ventricular angiography coupled with simultaneous recording of pressures with a micromanometer were used to determine end-systolic stress-to-volume ratio (ESSVR), end-systolic elastance (Ees), effective arterial elastance (Ea), external work (EW), and pressure-volume area (PVA). Myocardial contractile performance, assessed by Ees normalized by myocardial mass and by ESSVR, was lower in group I than in group 2 (1.23 +/- 0.28 v 1.89 +/- 0.48 mm Hg/mL/100 g, and 3.85 +/- 0.99 v 5.13 +/- 0.56 g/cm2/mL, respectively, both P < .001). Ventriculoarterial coupling evaluated through Ea/Ees ratio, and mechanical efficiency evaluated through EW/PVA ratio, were similar in the two groups (0.53 +/- 0.08 v 0.51 +/- 0.05, and 0.78 +/- 0.03 v 0.80 +/- 0.02, respectively, NS). In conclusion, this study shows that ventriculoarterial coupling and mechanical efficiency are comparable in hypertensive patients with and without LVH. These results suggest that in hypertensive patients, the matching between left ventricular performance and arterial load and the energy transfer are preserved either through left ventricular hypertrophy with moderate depression of myocardial contractile performance or through enhancement of myocardial contractile performance in patients with normal left ventricular mass.

[The REVEIL study: feasibility study of blood pressure self-monitoring. Preliminary results and patient opinions]

The REVEIL study is a pilot studies to determine the feasibility of self blood pressure measurement (SBPM). Feasibility was assessed by the quality of measurements and the patient opinion. This preliminary report focused on the patient opinion. Patients were included in the study by their general practitioner or cardiologist when he thought there was an indication for SBPM. Patients were excluded if their physical or mental autonomy was not sufficient to perform SBPM or if they were arrhythmic. The lending of the device was free (against a guarantee of 800 F) and it was available in one of the 44 drugstores that participated to the study. The physician performed patient education about SBPM and the druggist explained the handling of the device. SBPM was performed over a 7-day period: every day two series of 3 consecutive measurements were requested in the morning before taking the antihypertensive treatment, and in the evening between dinner and bedtime. The device was the validated OMRON 705 CP. 428 patients were included in the study. Among them, 385 (90%) accepted to participate to the study and 43 refused (10%). Almost half of the refusals were due to patients that did not want to take care of them and 16% were justified by a technical problem. Preliminary data included 362 patients aged 55.2 years, 79 of them older than 70 years. 80 patients (22%) experienced difficulties to perform SBPM, 28 of them (7.3%) to perform measurements and 13 (3.4%) to understand how worked the device. At the end of the study, 82 patients (23%) had better understanding of their hypertension, 90 patients (25%) felt themselves more motivated to take their medication and 111 patients (31%) found that their physician took better charge of them. 286 patients (79%) evaluated the overall satisfaction at SBPM. Among them, 276 patients (97%) were very satisfied (57%) or satisfied (40%) with SBPM when only 3% of patients were not. In summary, SBPM was easily performed in the conditions of the REVEIL study, and the majority of patients was satisfied with this experience.

[Inhibition of iron-catalyzed oxidative reactions restores mathcing between coronary blood flow and myocardial metabolic demand in type 2 diabetes]

In diabetes, endothelium-dependent dilation of large and small coronary arteries is impaired, which results in a mismatch between myocardial metabolic demand and coronary blood flow. It has been proved that deferoxamine, an iron chelator that inhibits Fenton and Haber-Weiss reactions, restores a normal response to cold pressor test and flow increase in angiographically normal epicardial coronary arteries of diabetic patients. This result suggests that nitric oxide could be inactivated by reactive oxygen species. The aim of this study was to assess the effects of deferoxamine on coronary microcirculation vasomotion when myocardial oxygen demand is increased by sympathetic stimulation elicited by cold pressor test in type 2 diabetic patients. In 17 patients with angiographically normal coronary arteries and without any other coronary risk factors, coronary blood flow has been measured using quantitative angiography and intracoronary Doppler at baseline and during a cold pressor test, before and after intravenous administration of 500 mg deferoxamine. Increase in rate-pressure product, an estimate of myocardial metabolic demand, was similar before and after deferoxamine (+21.1 +/- 8.7% vs +20.5 +/- 8.9%, respectively), but coronary blood flow increase was significantly higher after deferoxamine (+6.3 +/- 12.9% vs +31.8 +/- 16.7%, respectively, p < 0.001), and coronary resistance was increased before deferoxamine and decreased after (+14.8 +/- 21.9% vs -7.9 +/- 10.9%, respectively, p < 0.001). Moreover, before deferoxamine, the negative correlation between coronary blood flow and rate-pressure product changes before deferoxamine (R = 0.518, P < 0.05) was turned in a positive relationship after deferoxamine (r = 0.546, p < 0.05). In conclusion, in type 2 diabetic patients, endothelium-dependent dilation of the coronary microcirculation is restored when iron-catalysed oxidative reactions are inhibited by deferoxamine, which restores the normal matching between myocardial oxygen demand and coronary blood flow.

[REVEIL Trial: Study validity, information and logistics. Preliminary results. Quality measures]

Self blood pressure measurement (SBPM) is not fully applied because of the cost of devices and the lack of efficient dedicated medical networks. The aim of the REVEIL study was to allow patients to freely rent SBPM devices by their pharmacist after initial medical prescription. Practitioners taught SBPM methods to the patients with a booklet and the pharmacist explained them how to use the device. This preliminary report focuses on the 428 first patients included from September 1999 to June 2000 by their general practitioner (n = 59) or cardiologist (n = 12) in the centre of the city of Reims (France), when he thought there was an indication for a SBPM period. The patient received a medical prescription and took a validated device (Omron 705CP) by one of the 44 pharmacists who accepted to participate. After 7 days the patient consulted his practitioner with the filled booklet. The prescription was for 7 days with 3 measurements each morning (before intake of antihypertensive drugs) and each evening (12 hours later). Patients reported the results on the booklet and enclosed the report printed by the device. From the 428 included patients, 362 (85%) gave analyzable data, the difference being explained by refusals (n = 39) and by the lag between inclusion and completion. Mean age was 55.2 (range 20 to 90). Education levels were: no graduation (n = 71), primary school (n = 172), college (n = 59), university (n = 86) [no answer in n = 40]. Seventy nine percent (n = 286) performed at least 12 measurements on three consecutive days. There is no significant difference between morning and evening completions. According to themselves, 294 patients fully succeeded in SBPM. Eighteen failed (6 reported a failure of the device, 2 had not understood the procedure, 5 had forgotten, 5 reported another cause), 50 did not answer. These results establish the fair applicability of SBPM under the realistic conditions of the REVEIL study (free rent of devices after medical prescription) as 85% of patients gave contributive information with a good quality in 79% of them.

Impairment of coronary microvascular dilation in response to cold pressor--induced sympathetic stimulation in type 2 diabetic patients with abnormal stress thallium imaging

Coronary microcirculation dysfunction may be associated with myocardial perfusion defects on thallium imaging in diabetic patients without coronary artery stenosis. Microvascular coronary adaptation to increased myocardial oxygen demand in response to sympathetic stimulation evoked by the cold pressor test was examined in 22 type 2 diabetic patients with thallium imaging defects and in 15 control subjects. Both the diabetic patients and control subjects had angiographically normal coronary arteries and no other risk factors. Despite a similar increase in the rate-pressure product in the two groups (22.6 +/- 12.4% in diabetic patients and 31.8 +/- 8.2% in control subjects, NS), coronary blood flow increase in the left anterior descending artery (mean flow velocity measured by intracoronary Doppler multiplied by the cross-sectional area measured by digital angiography) was significantly lower in diabetic patients than in control subjects (14.7 +/- 19.8 vs. 75.5 +/- 13.5%, respectively; P = 0.0001). In addition, when there was a positive correlation between the two parameters in control subjects (r = 0.651, P < 0.01), there was no relationship in diabetic patients (r = 0.054). In conclusion, vasodilation of the coronary microcirculation in response to sympathetic stimulation evoked by the cold pressor test is impaired in type 2 diabetic patients without epicardial artery lesions. This microvascular impairment during sympathetic stimulation may explain exercise-induced myocardial perfusion abnormalities observed in these patients and may impair microcirculatory coronary vasodilation during current life stress episodes such as exercise, mental stress, or cold exposition.

Restoration of flow-dependent coronary dilation by ACE inhibition improves papaverine-induced maximal coronary blood flow in hypertensive patients: demonstration that large epicardial coronary arteries are more than conductance vessels

Restoration of flow-dependent coronary artery dilation by angiotensin-converting enzyme inhibition (ACEI) has been demonstrated in patients with hypertension. The aim of the present study was to evaluate whether dilation of conductance coronary arteries may alter maximal coronary blood flow (CBFmax) and minimal coronary resistance (CRmin) in hypertensive patients with reversible impairment of flow-dependent coronary artery dilation. Thirteen hypertensive patients with angiographically normal coronary arteries and no other risk factors were studied. Cross-sectional areas (CSAs) of proximal and distal left anterior descending (LAD) coronary arteries were determined by quantitative angiography. Coronary flow velocity was recorded in the distal LAD with an intracoronary Doppler catheter. Estimates of coronary blood flow and resistance were calculated at rest and during maximal increase in blood flow induced by papaverine injected in the midportion of the LAD, both before and after ACEI. Flow-dependent dilation of the proximal LAD, abolished before ACEI, was restored after (26.7 +/- 11.2%; p < 0.001). The increase in CSA of the distal LAD exposed to papaverine was significantly higher after ACEI than before (from 33.4 +/- 20.5% to 51.5 +/- 23.4%; p < 0.001). After restoration of proximal LAD flow-dependent dilation, CBFmax was increased by +21.0 +/- 10.3% (p < 0.001), and CRmin was reduced by 19.3 +/- 9.5% (p < 0.001). Thus, dilation of epicardial coronary arteries participates substantially in the coronary resistance in hypertensive patients. Restoration of flow-dependent coronary artery dilation by ACEI may improve the ability of coronary circulation to deliver its maximal myocardial blood flow in hypertensive patients.

[Dysfunction of the coronary microcirculation in type 2 diabetic patients]

A failure of coronary blood flow to increase during cold pressor test has been shown in patients with coronary atherosclerosis and impaired metabolic coronary vasodilatation in response to atrial pacing has been demonstrated in diabetic patients without significant epicardial artery stenoses. This study was designed to evaluate coronary microvascular adaptation to increased myocardial oxygen demand in response to sympathetic stimulation in diabetic patients with angiographically normal coronary arteries. Microvascular coronary adaptation to increased myocardial oxygen demand due to sympathetic stimulation evoked by the cold pressor test has been examined in 22 type 2 diabetic patients and in 15 control subjects with angiographically normal coronary arteries and no other risk factors. Coronary blood flow was calculated by measuring mean flow velocity in left anterior descending coronary artery by intracoronary Doppler and cross sectional area of the artery by digital angiography. Results show that despite a similar increase in rate-pressure product in the 2 groups (+22.6 +/- 12.4% in diabetic patients and +31.8 +/- 8.2% in control subjects, NS), coronary blood flow increase in left anterior descending artery was significantly lower in diabetic patients than in control subjects (+14.7 +/- 19.8% vs +75.5 +/- 13.5%, respectively, p = 0.0001). In addition, when there was a positive correlation between the 2 parameters in control subjects (R = 0.651, p < 0.01), there was no relationship in diabetic patients (R = 0.054). In conclusion, this study demonstrates that vasodilatation of coronary microcirculation in response to sympathetic stimulation evoked by cold pressor test is impaired in type 2 diabetic patients without epicardial artery lesions. This microvascular impairment during sympathetic stimulation may explain exercise-induced myocardial perfusion abnormalities observed in these patients and may impair microcirculatory coronary vasodilatation during current life stress episodes such as exercise, mental stress or cold exposure.

Effects of nicotine gum on coronary vasomotor responses during sympathetic stimulation in patients with coronary artery stenosis

Smoking-cessation rates may be improved by nicotine-replacement therapy that reduces withdrawal symptoms. However, nicotine may have adverse effects on coronary circulation. The purpose of this study was to examine the short-term effects of nicotine gum chewing on the dimensions of coronary arteries of patients with coronary artery disease and on the response of coronary vessels to sympathetic stimulation caused by the cold pressor test. In 17 patients who were past chronic cigarette smokers, cross-sectional areas of 32 coronary artery stenoses and 32 adjacent apparently normal segments were measured by using quantitative coronary angiography at baseline and after a cold pressor test before and after nicotine gum chewing. The cold pressor test produces an increase in arterial pressure without any change in heart rate. These changes were similar before and after nicotine gum. Before nicotine gum, the cross-sectional area of coronary stenoses and apparently normal segments was significantly and similarly reduced during the cold pressor test (-11+/-12% and -11+/-12%, respectively; both p values <0.0001 vs. baseline). After nicotine gum, baseline cross-sectional area was not modified, and response to the cold pressor test was similar to that observed before nicotine gum (-11+/-18% and -12+/-12%, respectively; both p values <0.0001 vs. baseline). In conclusion, nicotine-replacement therapy by using nicotine gum does not reduce the surface area of normal and diseased coronary segments and does not enhance the constricting effect of sympathetic stimulation produced by the cold pressor test. Thus nicotine gum may be considered a relatively safe drug in patients who need nicotine-replacement therapy to stop smoking.

[Left ventricular performance, ventriculo-arterial coupling and mechanical output in hypertensive patients with and without left ventricular hypertrophy]

Left ventricular hypertrophy (LVH) is a physiological process of adaptation of the heart to mechanical load increase. Despite depression of left ventricular (LV) contractile performance, work efficiency is preserved and ventriculoarterial coupling is almost normal in hypertensive patients with LVH. To assess the differences between patients with and without LVH, LV contractile performance, the ventriculoarterial coupling and mechanical efficiency were compared in 2 groups of hypertensive patients with similar body surface area and arterial pressures, 23 without LVH (group 1) and 30 with LVH (group 2) and compared to data of 20 normotensive subjects. Left ventricular angiography coupled with simultaneous recording of pressures with micromanometer were used to determine end-systolic stress-to-volume ratio (ESSVR), end-systolic elastance (Ees), effective arterial elastance (Ea), external work (EW) and pressure-volume area (PVA). Left ventricular contractile performance assessed by Ees/100 g myocardial mass and EESVR were lower in group 2 than in group 1 (1.23 +/- 0.28 vs 1.89 +/- 0.48 mmHg/mL/100 g and 6.22 +/- 1.07 vs 9.56 +/- 0.97 g/cm2/mL/m2, respectively, both p < 0.0001, control subjects: 1.47 +/- 0.41 and 6.97 +/- 1.22, respectively). Ventriculoarterial coupling evaluated through Ea/Ees ratio (0.51 +/- 0.05 in group 1 vs 0.53 +/- 0.08 in group 2, 0.49 +/- 0.09 in control subjects), and work efficiency evaluated through EW/PVA ratio (0.80 +/- 0.02 in group 1 vs 0.78 +/- 0.03 in group 2, 0.80 +/- 0.03 in control subjects), were similar in the 2 groups and were comparable to control subject values. In conclusion, this study shows that ventriculoarterial coupling and work efficiency are comparable in hypertensive patients with and without LVH. These results suggest that in patients without LVH the matching between left ventricle and arterial receptor is preserved through an enhancement of myocardial contractility which is energetically costly. Conversely, LVH seems to be a useful adaptation which minimizes the energetical cost of high pressure generation.

Left ventricular contractile performance, ventriculoarterial coupling, and left ventricular efficiency in hypertensive patients with left ventricular hypertrophy

Contractile performance of hypertrophied left ventricle may be depressed in arterial hypertension. Ventriculoarterial coupling is impaired when myocardial contractile performance is reduced and when afterload is increased. The left ventricular contractile performance and the ventriculoarterial coupling were evaluated in 30 hypertensive patients with moderate left ventricular hypertrophy and 20 control subjects. Left ventricular angiography coupled with the simultaneous recording of pressures with a micromanometer were used to determine end-systolic stress/volume index, the slope of end-systolic pressure-volume relationship, ie, end-systolic elastance, effective arterial elastance, external work, and pressure-volume area. In hypertensive patients, left ventricular contractile performance, as assessed by end-systolic elastance/ 100 g myocardial mass, was depressed (4.35 +/- 1.13 v 5.21 +/- 1.89 mm Hg/mL/100 g in control subjects P < .02), when end-systolic stress-to-volume ratio was comparable in the two groups (3.85 +/- 0.99 g/cm2/mL in hypertensive patients versus 3.51 +/- 0.77 g/cm2/mL in control subjects). Ventriculoarterial coupling, evaluated through effective arterial elastance/end-systolic elastance ratio, was slightly higher in hypertensive patients (0.53 +/- 0.08 v 0.48 +/- 0.09 mm Hg/mL in control subjects, P < .05), and work efficiency (external work/pressure-volume area) was similar in the two groups (0.78 +/- 0.04 mm Hg/mL in hypertensive patients versus 0.80 +/- 0.03 mm Hg/mL in control subjects). This study shows that despite a slight depression of left ventricular contractile performance, work efficiency is preserved and ventriculoarterial coupling is almost normal in hypertensive patients with left ventricular hypertrophy. Thus, it appears that left ventricular hypertrophy might be a useful means of preserving the match between left ventricle and arterial receptor with minimal energy cost.

Acute effects of angiotensin-converting enzyme inhibition on coronary vasomotion in hypertensive patients

Coronary vasodilator responses to pharmacological (acetylcholine) and physiological (cold pressor test and flow dependent dilation) stimuli are impaired in hypertensive patients. The ability of angiotensin-converting enzyme inhibitors to restore normal coronary responses in hypertension and the potential mechanisms involved are examined. In spontaneously hypertensive rats, angiotensin-converting enzyme inhibitors prevent impairment of endothelial-dependent relaxation of arterial rings in response to acetylcholine; in dogs, intracoronary infusion of an angiotensin-converting enzyme inhibitor dilates epicardial arteries and enhances coronary blood flow. In hypertensive patients with normal coronary arteries, intravenous administration of the angiotensin-converting enzyme inhibitor perindoprilat changes constriction of coronary arteries to dilation in response to the cold pressor test, and the absence of flow-dependent dilation becomes a normal response. In addition, maximal coronary blood flow induced by papaverine is enhanced by angiotensin-converting enzyme inhibition and minimal coronary resistance is reduced. It is concluded that both animal and human studies have demonstrated that angiotensin-converting enzyme inhibitors may acutely reverse the abnormalities of coronary vasomotion in arterial hypertension. However, not all the mechanisms responsible are fully understood and further studies are needed, particularly to determine the exact role of nitric oxide, bradykinin and oxygen-derived free radicals.

[Coronary endothelial dysfunction in hypertension]

Intracoronary injection of acetylcholine leads to coronary vasodilatation in normal subjects and vasoconstriction in hypertensive subjects, suggesting an abnormality of endothelial function in hypertension. In order to study the response to physiological stimulation which induces endothelium-dependent vasodilatation, the effects of sympathetic stimulation (cold pressor test) and of the increase in flow velocity in the left anterior descending artery were analysed in 10 control and 26 hypertensive subjects. All had angiographically normal coronary arteries and normal lipid profiles. None of the subjects were smokers or diabetic. During the cold test (12 patients), the flow velocity increased by 47 +/- 26% (p < 0.05) in controls and by 68 +/- 48% (p < 0.01) in the hypertensives. Dilatation of the coronary arteries was observed in controls (+12.0 +/- 4.5%, p < 0.001) and constriction in the hypertensives (-10.3 +/- 8.5%, p < 0.001). Injection of papaverine in the distal left anterior descending artery (14 patients) induced proximal dilatation in controls (+17.0 +/- 10.6%, p < 0.001) and was ineffective in hypertensives (-0.4 +/- 1.5%), whereas the flow velocity increased by 521 +/- 129% and 406 +/- 120% (p < 0.001) respectively. Intracoronary injection of 2 mg of isosorbide dinitrate induced comparable dilatation in control subjects (+30.0 +/- 12.9%, p < 0.001) and in the 26 hypertensives (+22.8 +/- 6.5%, p < 0.001). In 10 hypertensive patients, intravenous injection of an angiotensin converting enzyme inhibitor, perindoprilat, immediately re-established the vasodilatory response to these two stimuli. The authors conclude that the coronary responses to physiological stimuli (sympathetic stimulation, increase in flow velocity) are altered in hypertensive subjects with angiographically normal coronary arteries with no other risk factors. Normal vasomotion may be restored by an angiotensin converting enzyme inhibitor.

[Ventriculoarterial coupling and left ventricular performance in hypertensive patients with left ventricular hypertrophy]

It has been shown that 1) contractile performance of hypertrophied left ventricle (LV) of hypertensive patients (HP) is depressed, and 2) ventriculoarterial (VA) coupling is altered when myocardial contractile performance is reduced and when afterload is increased. To assess the relationship between contractile performance of hypertrophied LV and the VA coupling in hypertensive patients. LV angiography coupled with simultaneous recording of pressures with micromanometer were used to determine end-systolic stress/volume index ratio (ESS/ESVi), the slope of end-systolic pressure-volume relationship, i.e. end-systolic elastance (Ees), effective arterial elastance (Ea), external work (EW) and pressure-volume area (PVA). Comparison of results in 30 HP and 20 control subjects (CS) showed that LV contractile performance assessed by Ees/100 g left ventricular myocardial mass (LVM, echocardiographic determination) was depressed (HT: 4.35 +/- 1.13; CS: 5.21 +/- 1.89 mmHg/ml/100 g; p < 0.02) and was negatively correlated to the LVM (Ees = -0.026 LVM + 3.363; r = 0.581; p < 0.001), when ESS/ESVi, another estimate of LV contractile performance, was comparable in the 2 groups (6.66 +/- 1.55 g/cm2/ml/m2 in HT vs 6.72 +/- 1.36 in CS; NS) and negatively correlated with the LVM (ESS/ESVi = -0.019 LVM + 8.947; r = 0.369; p < 0.01). Ventriculoarterial coupling evaluated through Ea/Ees ratio (Ea and Ees in mmHg/ml/m2) was slightly higher in HT (0.53 +/- 0.08 vs 0.48 +/- 0.09 in CS; p < 0.05), work efficiency (EW/PVA) was similar in the 2 groups (0.78 +/- 0.04 in HP vs 0.80 +/- 0.03 in CS) and PVA, which is representative of the myocardial oxygen demand per beat, is negatively related to LVM (PVA = -0.003 MVG + 1.44; r = 0.434; p < 0.01).

CONCLUSIONS

this study shows that despite a slight depression of LV contractile performance, work efficiency is preserved and ventriculoarterial coupling is almost normal in HP with LV hypertrophy. Thus, it appears that LV hypertrophy might be a useful means of preservation of matching LV and arterial receptor with minimal energetical cost.

Coronary vascular reserve is similarly reduced in hypertensive patients without any other coronary risk factors and in normotensive smokers and hypercholesterolemic patients with angiographically normal coronary arteries

Hypertensive patients (HTP) with left ventricular hypertrophy have reduced coronary vascular reserve (CVR), but in HTP without left ventricular hypertrophy, CVR is within the normal range according to values determined in subjects without taking into account coronary risk factors such as cigarette smoking or hypercholesterolemia. To examine the influence of hypertension, cigarette smoking, and hypercholesterolemia on coronary flow and resistance reserve, coronary flow velocity was measured using a Doppler catheter before and after a maximally vasodilating dose of papaverine in 15 normotensive subjects without any coronary risk factors (Group 1), in 12 nonsmoker HTP with normal lipid profiles who had never been treated (Group 2), in 8 normotensive smoker patients (Group 3), in 9 normotensive nonsmoker patients with hypercholesterolemia (Group 4), and in 13 normotensive smoker patients with hypercholesterolemia (Group 5). All patients had normal coronary arteriography and left ventricular mass and function. Peak-to-resting coronary flow velocity ratio and mean aortic pressure were used to determine coronary flow reserve (CFR) and a minimal coronary vascular resistance index (MCVRI). Results show that in groups 2, 3, 4, and 5 comparatively to Group 1, CFR was similarly reduced (4.60 +/- 0.74 [P < .001], 4.59 +/- 0.35 [P < .001], 5.01 +/- 0.55 [P < .05], 5.03 +/- 0.78 [P < .05], groups 2 to 5, respectively, compared to group 1 5.66 +/- 0.68), and that MCVRI was similarly augmented (0.19 +/- 0.03 [P < .01], 0.20 +/- 0.0 [P < .001], 0.19 +/- 0.02 [P < .05], 0.19 +/- 0.03 [P < .05], groups 2 to 5, respectively, compared to group 1 0.16 +/- 0.02). In conclusion, HTP without left ventricular hypertrophy have a similar reduction of their CVR as smokers and hypercholesterolemic patients when compared to a group of subjects without any coronary risk factors. This should be taken into account when determining a group of control subjects for coronary reserve.

Angiotensin-converting enzyme inhibition restores flow-dependent and cold pressor test-induced dilations in coronary arteries of hypertensive patients

BACKGROUND

Cold pressor test (CPT)-induced and flow-dependent epicardial coronary artery dilations are impaired in patients with hypertension. ACE inhibition can attenuate sympathetic coronary constriction and potentiate or restore endothelium-dependent relaxations. This study was designed to determine whether the ACE inhibitor perindoprilat can restore normal coronary dilative responses in hypertensive patients.

METHODS AND RESULTS

Coronary vasomotor responses to CPT and to maximal increase of blood flow induced by papaverine were studied in 10 untreated patients with essential hypertension, no other risk factors, and angiographically normal coronary arteries before and after intravenous ACE inhibition by perindoprilat. Diameters of proximal and distal left anterior descending (LAD) and circumflex coronary arteries were measured by quantitative angiography. Estimates of coronary blood flow and resistance index were calculated with an intracoronary Doppler catheter in the distal LAD. Perindoprilat did not modify the hemodynamic responses to CPT and papaverine. In response to CPT, perindoprilat changed the epicardial coronary constriction (-8.4 +/- 5.8%, P < .001) into a significant dilation (+12.0 +/- 6.4%, P < .001). Perindoprilat significantly increased the coronary blood flow (from 33.7 +/- 10.0 to 57.9 +/- 20.5 mL/min, P < .01) and enhanced the decrease in coronary resistance (from 4.28 +/- 1.27 to 2.96 +/- 0.84 mm Hg.mL-1.min-1, P < .001) caused by CPT. Flow-dependent dilation of the proximal LAD was abolished in the control condition and was restored after perindoprilat (12.6 +/- 4.7%, P < .001).

CONCLUSIONS

ACE inhibition restored CPT-induced and flow-mediated coronary artery dilations in patients with essential hypertension. These results indicate that impaired coronary vasomotor responses may be reversible in recently diagnosed hypertension.

Epicardial coronary arteries are not adequately sized in hypertensive patients

OBJECTIVES

This study sought to compare coronary artery dimensions in hypertensive patients and normal subjects.

BACKGROUND

Myocardial oxygen demand at rest and corresponding coronary blood flow are the main determinants of large coronary artery dimensions in humans. Coronary diameters are increased in aortic valve disease.

METHODS

Left main, proximal and distal left anterior descending and proximal circumflex coronary artery diameters were measured by quantitative angiography in 10 control subjects (group 1) and 26 untreated hypertensive patients, 12 without (group 2a) and 14 with (group 2b) left ventricular hypertrophy. All patients had normal cholesterol levels and angiographically normal coronary arteries. Measurements were made at baseline and after 2 mg of intracoronary isosorbide dinitrate to obtain maximal dimensions of vessels. Coronary flow velocity was measured in the distal left anterior descending coronary artery by Doppler ultrasound.

RESULTS

Despite a higher rate-pressure product in hypertensive patients, all segment diameters were slightly but not significantly higher at baseline in group 2b than in groups 1 and 2a. Diameters were similar in the three groups after isosorbide dinitrate. Conversely, coronary flow velocity was significantly higher in hypertensive patients than in group 1 either at baseline (10.4 +/- 2.2 [mean +/- SD] cm/s [group 2a] and 12.8 +/- 2.4 cm/s [group 2b] vs. 6.5 +/- 2.0 cm/s [group 1], all p < 0.001) or after isosorbide dinitrate (6.8 +/- 2.8 cm/s [group 2a] and 7.8 +/- 2.1 cm/s [group 2b] vs. 3.7 +/- 0.8 cm/s [group 1], p < 0.01 and p < 0.001, respectively).

CONCLUSIONS

Despite an elevated myocardial oxygen demand, maximal dimensions of large coronary arteries are not increased in hypertensive patients, resulting in an elevated coronary flow velocity that may increase longitudinal shear stress at the endothelial surface. This elevated flow velocity might be an important determinant in the pathogenesis of atherosclerosis in hypertensive patients.

Dipyridamole slows the rate of isovolumic pressure fall in patients with normal coronary arteries

Dipyridamole is currently used for thallium imaging and stress echocardiography. The coronary and haemodynamic effects of dipyridamole are well documented while its effects on left ventricular relaxation remain to be determined. The aim of the present study was to evaluate the effects of dipyridamole on left ventricular relaxation rate in healthy subjects. High fidelity pressure recordings were obtained at fixed atrial pacing (89 +/- 2 beats.min-1) in 10 subjects with normal left ventricular angiography and coronary arteriograms. Left ventricular pressure was recorded at rest and 5 min after a 4 min infusion of dipyridamole (0.14 mg.kg-1.min-1). Dipyridamole infusion decreased left ventricular systolic pressure (P < 0.01) and time to left ventricular systolic pressure (P < 0.01), with no changes in end-diastolic pressure or peak rate of pressure rise. The peak rate of isovolumic pressure fall decreased (from 1957 +/- 105 to 1488 +/- 100 mmHg.s-1, P < 0.01) and the time constant of isovolumic relaxation increased (from 37 +/- 2 to 44 +/- 3 ms, P < 0.02). In conclusion, our study indicates that acute administration of clinically relevant doses of dipyridamole displays deleterious effects on heart relaxation in healthy humans.

Coronary vascular reserve in humans: a critical review of methods of evaluation and of interpretation of the results

The concept of coronary vascular reserve stems from the description of coronary autoregulation by Mosher in 1964. Schematically, the coronary blood flow at rest depends on the determinants of myocardial oxygen demand (heart rate, contractility and ventricular load). If maximal coronary vasodilation is produced, it results in a linear and steep pressure-flow relationship. The increment of coronary flow above its basal value is called the coronary flow reserve, which indicates the flow added to the basal flow for a given coronary perfusion pressure when the coronary vascular bed is maximally dilated. Thus, in the absence of epicardial coronary artery stenosis, the maximal coronary flow is a function of the coronary perfusion pressure and of the maximal surface area of the coronary circulation at the resistance vessel level. Evaluation of the coronary reserve in humans raises three major concerns: (1) methods for measuring or evaluating coronary flow are imprecise and inconvenient (diffusible indicators), invasive (coronary sinus thermodilution, intracoronary Doppler), expensive and require sophisticated technology (ultrafast computed tomography, positron emission tomography), or in the process of being validated (contrast echocardiography, transoesophageal Doppler echocardiography, myocardial scintigraphy: (2) the compounds used to produce maximal coronary vasodilation are administered either by the intracoronary route (papaverine) or intravenously (dipyridamole, adenosine); (3) how to interpret the data: is the alteration of the coronary reserve due to a modification of the basal coronary flow or/and of the maximal coronary flow? Thus, each method has its own limitations and constraints that must be taken into account in order to avoid crude misinterpretations. In conclusion, the measurement of coronary reserve may be an important means of understanding coronary physiology and pathophysiology. Recently developed non-invasive methods (ultrafast computed tomography, positron emission tomography, echography) and the ability to produce maximal coronary vasodilation by the intravenous route are promising.

[Restoration of normal coronary vasomotricity after intravenous infusion of angiotensin converting-enzyme inhibitor (perindoprilat) in hypertensive patients]

We have previously shown that in hypertensive patients, the response of normal coronary arteries to sympathetic stimulation evoked by the cold-pressor test (CPT), and the endothelial-mediated flow-dependent coronary vasodilation were impaired. The immediate effects of the converting-enzyme inhibitor perindoprilat (PER) have been evaluated in 10 untreated hypertensive patients with angiographically normal coronary arteries and results have been compared to the normal responses of 10 control subjects. Diameter changes of proximal left anterior descending coronary artery (pLAD) and coronary flow velocity in distal LAD have been measured at baseline, during CPT, during recontrol, and after 10 mg papaverine (PAP) injection in the mid portion of the LAD. Measures have been repeated after intravenous infusion of 1 mg PER, and at the end of the procedure after 2 mg intracoronary injection of isosorbide dinitrate (ISDN). Left ventricular dimensions and systolic function, total cholesterol, triglycerides, HDL and LDL-cholesterol were within the normal range. In hypertensive patients before PER, pLAD constricted in response to the CPT and no diameter change was observed after PAP, despite the increase in flow velocity in the 2 conditions (+63 +/- 27%, and +412 +/- 77%, respectively; all p < 0.001). In control subjects, pLAD dilated significantly in these 2 conditions. In hypertensive patients after PER, pLAD dilated similarly to control subjects in the 2 conditions. Endothelium-independent coronary dilation to ISDN was comparable in the 2 groups of patients. In conclusion, PER restores a normal coronary response both to sympathetic stimulation due to CPT and to flow increase in hypertensive patients with angiographically normal coronary arteries and without any other coronary risk factors.

[Coronary artery caliber is not adapted to myocardial oxygen demand in hypertensive patients with angiographically normal coronary arteries]

Resting myocardial oxygen demand and corresponding coronary blood flow are main determinants of large coronary artery dimensions in humans. To examine the adaptation of epicardial coronary arteries to the increased myocardial oxygen demand, myocardial blood flow, in hypertensive patients, diameters of proximal and distal left anterior descending coronary artery (pLAD and dLAD), and proximal circumflex artery (CX) were determined in 15 untreated hypertensive patients and in 10 control subjects by quantitative angiography. All patients had total cholesterol < or = 5.40 mmol/l, LDL-cholesterol < or = 3.35 mmol/l, and angiographically normal coronary arteries. Measurements were made at base and after 2 mg intracoronary isosorbide dinitrate (ISDN) in order to obtain maximal dimensions of vessels. Coronary flow velocity was measured in distal left anterior descending coronary artery by Doppler. Results show that despite higher rate-pressure product in hypertensive patients, the diameters of the coronary segments were similar in control subjects and in hypertensive patients at base (3.53 +/- 0.84 vs 3.76 +/- 0.48 mm for pLAD; 2.55 +/- 0.50 vs 2.49 +/- 0.52 mm for dLAD; 2.92 +/- 0.40 vs 2.78 +/- 0.83 mm for CX, respectively). After intracoronary ISDN, diameters were also comparable between the 2 groups (4.54 +/- 0.86 vs 4.58 +/- 0.60 mm for pLAD; 3.35 +/- 0.58 vs 3.22 +/- 0.61 mm for dLAD; 3.47 +/- 0.56 vs 3.53 +/- 1.01 mm for CX, respectively). Conversely, coronary flow velocity was significantly higher in hypertensive patients at base (10.72 +/- 2.20 vs 6.48 +/- 2.01 cm/s; p < 0.001) and after ISDN (6.59 +/- 2.62 vs 3.72 +/- 0.87 cm/s; p < 0.001). Despite an elevated myocardial oxygen demand, large coronary artery dimensions are not increased in hypertensive patients resulting in an elevated coronary flow velocity that may increase longitudinal shear stress at the endothelial surface. This might be an important determinant in the pathogenesis of atherosclerosis in hypertensive patients.

Impairment of flow-dependent coronary dilation in hypertensive patients. Demonstration by cold pressor test induced flow velocity increase

In normal coronary arteries, increased flow velocity induces endothelium-dependent dilation, and dilation in response to sympathetic stimulation evoked by the cold pressor test is partly due to increased flow velocity. In arterial hypertension, angiographically normal coronary arteries were constricted by acetylcholine, an endothelium-dependent vasodilator. To assess the epicardial coronary artery response to the increase blood flow velocity induced by the cold pressor test in hypertensive patients with angiographically normal coronary arteries, coronary artery diameters and flow velocity were measured during cold pressor test in 12 untreated hypertensive patients and in 10 control subjects. Diameters were determined by quantitative angiography on proximal and distal segments of the left anterior descending coronary artery, and flow velocity measurements were made by Doppler testing in the distal segment. In control subjects, the proximal and distal segments dilated during cold pressor test by 12.0 +/- 4.5% and 13.9 +/- 6.5%, respectively (both P < .001), when flow velocity increased by 46.7 +/- 26.1% (P > .05). In hypertensive patients, segments were constricted, respectively, by 10.3 +/- 8.5% (P < .001) and 7.9 +/- 8.6% (P < .01), when the flow velocity was increased by 68.3 +/- 48.2% (P < .001). Intracoronary injection of an endothelium-independent dilator resulted in similar dilation in control subjects (proximal: +30.0 +/- 12.9%; distal: +32.4 +/- 15.2%) and in hypertensive patients (proximal: +22.3 +/- 7.5%; distal: +28.8 +/- 15.4%). In conclusion, in hypertensive patients with angiographically normal coronary arteries and without any other coronary risk factors, endothelium-dependent flow-mediated coronary dilation evoked by the cold pressor test is impaired.(ABSTRACT TRUNCATED AT 250 WORDS)

Loss of flow-dependent coronary artery dilatation in patients with hypertension

BACKGROUND

Abnormal endothelium-dependent coronary response to acetylcholine has been shown in patients with essential hypertension. We tested the hypothesis that flow-dependent dilatation, which has been shown in normal human coronary arteries, is impaired in hypertensive patients.

METHODS AND RESULTS

The coronary vasomotor response to maximal increase of blood flow induced by papaverine was studied in 10 control subjects and in 14 hypertensive patients with no other risk factors and angiographically normal coronary arteries. After the injection of papaverine in the midportion of the left anterior descending coronary artery (LAD), the diameter of the proximal LAD (LAD1) was measured by quantitative angiography, whereas that of the proximal circumflex artery (LCx) served as control segment. Estimates of coronary blood flow in the distal LAD (LAD2) were calculated by intracoronary Doppler flow velocity measurements. An increase in LAD2 blood flow of 521 +/- 41% (P < .001) in control subjects was associated with a 17.0 +/- 3.3% dilatation of the LAD1 (P < .001) and with no significant change in the diameter of the LCx. In hypertensive patients, despite a comparable increase in LAD2 blood flow of 406 +/- 32% (P < .001), the LAD1 failed to dilate (-0.4 +/- 0.6%, NS). The dilative response to isosorbide dinitrate was similar in control subjects and hypertensive patients (30.0 +/- 4.1%, P < .001 and 21.9 +/- 1.9%, P < .001, respectively).

CONCLUSIONS

Thus, the flow-mediated coronary dilatation is lost in hypertensive patients, and this may impair normal dilatation observed in response to an increase in myocardial metabolic demand.

Left ventricular diastolic function in asymptomatic and symptomatic human immunodeficiency virus carriers: an echocardiographic study

Acquired immunodeficiency syndrome (AIDS) is a systemic illness affecting multiple organs, including the heart. Left ventricular (LV) diastolic dysfunction has been reported as the first echocardiographically detectable abnormality in several cardiovascular disorders. We tested the hypothesis that Human Immunodeficiency Virus (HIV) carriers have LV diastolic impairment when studied early in the clinical course of the infection. Doppler echocardiographic and computerized time-motion parameters of LV diastolic function were obtained in 51 HIV patients and in 25 age- and sex-matched healthy controls. The HIV population consisted of 28 totally asymptomatic subjects and 23 patients with incipient AIDS. As compared to controls, the HIV group had similar heart rate, blood pressure level, LV dimensions and fractional shortening, but increased isovolumetric relaxation time (P = 0.03), early filling duration (P < 0.001) and decreased early mitral flow peak velocity (E) (P = 0.02) and EF slope (P < 0.001). HIV patients also showed lower values for posterior wall thinning (PWT, P < 0.01) and peak lengthening velocity of the posterior wall (PVL, P < 0.05), and a trend to a decreased peak rate of LV enlargement in diastole (D+, P = 0.05). Doppler-derived parameters of diastolic function were significantly altered in the asymptomatic HIV group vs controls. The LV diastolic indices were similar in symptomatic and asymptomatic HIV patients except for PWT, which was lower in the symptomatic HIV group (P = 0.04). Since mild and focal wall motion abnormalities were detected in 11 HIV carriers (22%), comparison of LV diastolic indexes between HIV patients and controls was also performed in two subgroups; these included asymptomatic (n = 26) and symptomatic (n = 14) patients with normal contractile state. The two subgroups had abnormalities of diastolic function similar to those of the HIV group as a whole, but with somewhat lower levels of statistical significance. Our data strongly suggest that there is myocardial involvement at the early stage of HIV infection; however, its impact on the clinical course of the disease remains to be clarified.

Clinical review of perindopril in the treatment of hypertension

Perindopril is a long acting angiotensin-converting enzyme inhibitor with a perhydroindole group and no sulphydryl radical. Perindopril is a pro-drug that is hydrolyzed to the active metabolite perindoprilat. Perindopril is rapidly absorbed, reaching peak plasma concentrations about 1 h after a single oral dose. Its bioavailability is greater than 70% and is not influenced by meals. Perindoprilat reaches peak plasma concentrations 3 to 4 h after administration. The blood pressure lowering effect of perindopril has been shown in animal models with spontaneous and renovascular hypertension. In hypertensive patients dose response studies have shown a significant and linear relationship between the dose and the activity of perindopril. The antihypertensive efficacy of 4 and 8 mg doses is significantly greater than that of 2 mg or of placebo. The maximal response is attained about 4 to 6 h after the first dose. As demonstrated by 24 h blood pressure recordings in ambulatory patients, the antihypertensive activity of perindopril was still significant 24 h after the last dose. Clinical trials have indicated that perindopril is at least as effective as usual therapeutic doses of captopril, atenolol or a combination of hydrochlorothiazide plus amiloride in mild to moderate essential hypertension. Oral administration of 4 to 8 mg od significantly reduced supine and standing systolic and diastolic blood pressure, and adequate diastolic blood pressure control was attained in about 60 to 70% of patients with monotherapy. In the majority of patients, hypertension was controlled with a daily dose of 4 mg.(ABSTRACT TRUNCATED AT 250 WORDS)

[Changes in coronary vasodilation in hypertensive patients with angiographically normal coronary arteries]

In normal subjects, coronary arteries dilate in response to sympathetic stimulation evoked by the cold pressor test. Similarly, in normal coronary arteries the increase in blood flow velocity induced by papaverine results in flow-dependent coronary dilation. In order to assess the coronary responses to both stimuli in hypertensive patients, variations of proximal left anterior descending coronary artery diameters and coronary blood flow velocity have been measured using quantitative coronary angiography and intracoronary Doppler in 10 control subjects and in 12 hypertensive patients. All the patients had angiographically normal coronary arteries. Total serum cholesterol, triglycerides, HDL- and LDL-cholesterol were within normal range in all patients. All patients were nonsmokers and none of them had diabetes mellitus. During the cold pressor test (hands immersed in ice water for 120 s), the rate-pressure product and coronary blood flow velocity increased respectively by 33 +/- 9% (p < 0.001) and 51 +/- 26% (p < 0.05) in control subjects, by 28 +/- 18% (p < 0.001) and 68 +/- 52% (p < 0.05) in hypertensive patients. In control subjects, coronary arteries dilated by + 12.0 +/- 4.4% (p < 0.001), and constricted by -10.3 +/- 8.5% (p < 0.001) in hypertensive patients. After injection of 10 mg of papaverine into the distal left anterior descending coronary artery, proximal left anterior descending coronary artery dilated by + 17.0 +/- 10.6% (p < 0.001) in control subjects, and did not vary (-0.7% +/- 10.6%) in hypertensive patients, when blood flow velocity was increased respectively by 449 +/- 97% and 383 +/- 103% (p < 0.001 in both groups).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary artery constriction caused by the cold pressor test in human hypertension

Hypertensive patients with angiographically normal coronary arteries may have myocardial ischemia when metabolic demand increases. Abnormal epicardial coronary artery vasomotion in response to sympathetic stimulation may contribute to ischemia in such patients. We studied the vasomotor response of smooth coronary arteries to a cold pressor test in 10 hypertensive patients without other risk factors and in 9 control subjects. Vessel dimensions were measured by quantitative angiography, and blood flow was calculated using an intracoronary Doppler catheter in the left anterior descending coronary artery. In response to cold pressor stimulation, arteries of control subjects dilated 13.0 +/- 5.9% (P < .001), and they constricted 8.2 +/- 8.5% in hypertensive patients (P < .001). Rate-pressure product increased from 9466 +/- 1677 to 12,547 +/- 2367 beats per minute (bpm).mm Hg in control subjects (P < .001) and from 13,720 +/- 1823 to 17,353 +/- 2037 bpm.mm Hg in hypertensive patients (P < .001). Coronary blood flow velocity and blood flow increased 51 +/- 26% (P < .05) and 87 +/- 27% (P < .001), respectively, in control subjects and 68 +/- 52% (P < .05) and 36 +/- 33% (P < .01) in hypertensive patients. At peak cold pressor test, despite a significant higher rate-pressure product in hypertensive patients, blood flow was similar in both groups, suggesting an uncoupling between myocardial metabolic demand and supply. Thus, hypertension impairs the vasodilator response of angiographically normal coronary arteries to a cold pressor test. This abnormal response may be due to enhanced catecholamine reactivity and/or impairment of endothelial flow-mediated vasodilator response.

Coronary vasodilator reserve in untreated and treated hypertensive patients with and without left ventricular hypertrophy

OBJECTIVES

This study was initiated to compare the coronary reserve in treated hypertensive patients with and without left ventricular hypertrophy with that in untreated patients.

BACKGROUND

Coronary reserve is impaired in hypertensive patients with left ventricular hypertrophy and normal coronary arteries. Moreover, basal coronary resistance is elevated in hypertensive patients without left ventricular hypertrophy.

METHODS

Coronary reserve was measured with a coronary Doppler catheter before and after a maximally vasodilating dose of intracoronary papaverine (peak/rest flow velocity ratio) in 16 control subjects and 37 hypertensive patients with normal epicardial coronary arteries. Among 20 untreated hypertensive patients, myocardial mass was increased in 11 (group 2a) and normal in 9 (group 2b). Seventeen patients had been treated effectively for at least 1 year; nine (group 3a) had persistent left ventricular hypertrophy, and eight (group 3b) had no left ventricular hypertrophy before treatment. Left ventricular volumes and ejection fraction were normal in all groups.

RESULTS

Coronary reserve was moderately reduced in group 2b (3.5 +/- 0.6 vs. 5.2 +/- 0.8 in control subjects, p < 0.001) and markedly diminished in groups 2a and 3a (2.5 +/- 0.5 and 2.7 +/- 0.4, respectively; all p < 0.001 vs. control subjects). In group 3b, coronary reserve was comparable to that of control subjects (5.1 +/- 1.4).

CONCLUSIONS

The reduction in coronary reserve observed in untreated hypertensive patients with normal myocardial mass suggests that structural abnormalities of the coronary microvasculature may occur before left ventricular hypertrophy. Treated patients with normal mass before treatment had a coronary reserve comparable to that of normotensive control subjects, whereas normalization of arterial pressure with persistent left ventricular hypertrophy was associated with a marked impairment of coronary reserve.

[Coronary vasoconstriction induced by acetylcholine in young smokers with normal angiographic coronary vessels]

Cigarette smoking is a major risk of coronary artery disease. Acetylcholine-induced coronary artery constriction has been reported in patients with normal coronary arteries and other risk factors. To evaluate coronary artery endothelial function in smokers, coronary artery responses to acetylcholine (10(-8) M to 10(-5) M) were analyzed by quantitative angiography in 5 young heavy-smokers and in 5 age-matched nonsmokers. All patients were normotensive, had normal left ventricular function and coronary arteries. Cholesterol, triglycerides, high- and low-density lipoproteins were within normal range. Vessel dimensions were measured on 4 segments of left coronary artery in all patients. In smokers, no change was produced at 10(-8) M and 10(-7) M acetylcholine concentration, but progressive diameter reduction was observed at 10(-6) M and 10(-5) M acetylcholine concentration. In nonsmokers, a dose-dependent dilation was produced from 10(-8) M to 10(-6) M acetylcholine concentration. No change was observed at 10(-5) M acetylcholine concentration. In the 2 groups, all segments dilated similarly after intracoronary isosorbide dinitrate.

CONCLUSION

This study reveals that in heavy-smokers the response of normal coronary arteries to acetylcholine is altered. Thus, endothelial dysfunction may be an early marker for coronary events in cigarette smokers.

Acetylcholine-induced constriction of angiographically normal coronary arteries is not time dependent in transplant recipients. Effects of stepwise infusion at 1, 6, 12 and more than 24 months after transplantation

OBJECTIVES

The aim of this study was to evaluate whether acetylcholine may be a useful tool for detection of early angiographically undetectable coronary atherosclerosis in heart transplant recipients.

BACKGROUND

Coronary artery disease is the main determinant of long-term prognosis in transplant recipients. Acetylcholine-induced constriction of angiographically normal coronary arteries in heart transplant recipients could be due to early atherosclerosis, and acetylcholine has been proposed for early detection of coronary artery disease.

METHODS

The responses of large coronary arteries to stepwise intracoronary infusion of acetylcholine (10(-8) to 10(-5) mol/liter) were compared in five control subjects and in four groups of transplant recipients 1, 6, 12 and > 24 months postoperatively (group 1, n = 6; group 2, n = 7; group 3, n = 6; group 4, n = 6, respectively). All patients had normal coronary arteriographic findings. Vessel dimensions were measured in four segments in each patient.

RESULTS

In control subjects, acetylcholine increased diameters significantly at 10(-8), 10(-7) and 10(-6) mol/liter (all p < 0.001 vs. basal value). No significant variation was observed at 10(-5) mol/liter. Intracoronary isosorbide dinitrate increased diameters of all segments (p < 0.001). In transplant recipients, vessel diameters did not vary significantly from baseline at 10(-8) and 10(-7) mol/liter concentrations in groups 1 and 3 and at 10(-8) mol/liter in group 4. Vessels constricted significantly in all the other cases. Comparisons of each group with control subjects showed that responses were significantly different for all concentrations but 10(-8) mol/liter in groups 3 and 4. Intracoronary isosorbide dinitrate elicited coronary vasodilation similar to that of control subjects in all groups of transplant recipients.

CONCLUSIONS

This study indicates that the acetylcholine response is persistently abnormal in transplant recipients compared with that in normal control subjects and that this abnormality may not be related simply to the presence of atherosclerosis. Thus, acetylcholine may not be a useful tool for early detection of coronary atherosclerosis in heart transplant recipients.

Acetylcholine-induced coronary vasoconstriction in young, heavy smokers with normal coronary arteriographic findings

PURPOSE

Cigarette smoking is a major coronary risk factor. Acetylcholine dilates coronary arteries in normal subjects, but acetylcholine-induced coronary constriction has been reported in patients with normal coronary arteriographic findings and other risk factors for coronary artery disease. The purpose of the present study was to evaluate the epicardial coronary artery response to acetylcholine in young, heavy smokers.

SUBJECTS AND METHODS

Responses to stepwise infusion of acetylcholine (10(-8)M, 10(-7)M, 10(-6)M, and 10(-5)M) into the left coronary artery were studied in five young, heavy smokers and in five age-matched nonsmokers. All subjects were normotensive and had normal left ventricular function and coronary arteriographic findings. Levels of serum cholesterol, triglycerides, and low-density lipoprotein levels were within normal ranges. Vessel dimensions were measured on four different segments in each subject, with quantitative digital-substracted arteriography.

RESULTS

In smokers, no change was produced at the 10(-8) M and 10(-7) M concentrations of acetylcholine, but progressive diameter reduction was observed at 10(-6) M and 10(-5) M acetylcholine (-26.6% +/- 13.6%, p < 0.001; -42.2% +/- 9.5%, p < 0.001, respectively). In nonsmokers, a progressive diameter dilation was produced from 10(-8) M to 10(-6) M acetylcholine (+5.3% +/- 3.6%, p < 0.001; +12.4% +/- 6.5%, p < 0.001; +15.9% +/- 6.9%, p < 0.001, respectively), and no change was observed at 10(-5) M acetylcholine. In the two groups, all segments dilated after infusion of intracoronary isosorbide dinitrate.

CONCLUSION

The abnormal coronary vasoconstriction induced by acetylcholine in young, heavy smokers with angiographically normal coronary arteries suggests an endothelial vasodilator dysfunction. This mechanism may contribute to the pathogenesis of coronary artery disease in cigarette smokers.

Acceptability of perindopril in mild-to-moderate chronic congestive heart failure. Results of a long-term open study in 320 patients

The long-term acceptability of perindopril in mild-to-moderate chronic heart failure (CHF) was evaluated in a multicenter open study. A total of 320 patients with a mean age of 62 +/- 1 years and CHF of New York Heart Association (NYHA) class I (2 patients), II (204 patients), or III (114 patients) were included after a 2-week run-in period during which time vasodilators were stopped and diuretic and/or digoxin therapy stabilized. Perindopril treatment was started at 2 mg, increasing to 4 mg once daily after 2 weeks if supine systolic blood pressure remained > 100 mm Hg. After this dose titration period, follow-up visits were scheduled at monthly intervals for the first 3 months, then at 3-month intervals with a maximum period of follow-up being 30 months. At the time of analysis, mean duration of treatment was 276 days and 208 patients were treated > or = 6 months. Of the 320 patients, 10 (3.1%) died, 9 (2.8%) were withdrawn for worsening heart failure, and 38 (11.9%) for nonfatal adverse events, including cough (2.8%), dizziness or orthostatic discomfort (1.9%), angina pectoris (1.6%), and cutaneous signs (1.3%). Exercise test duration increased from 516 +/- 14 to 659 +/- 19 sec after 6 months of treatment (p < 0.01). At 6 months, 55.6% of patients improved by at least 1 NYHA class. Supine systolic blood pressure decreased slightly from 137 +/- 2 to 132 +/- 1 mm Hg (p < 0.01) and plasma creatinine levels remained stable from 100 +/- 2 to 102 +/- 2 mumol/liter after 6 months of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Myocardial contractility, lusitropy and calcium responsiveness in young (50 days) and hypertrophied (180 days) cardiomyopathic hamsters

Contractility, lusitropy and responsiveness to the increase of external Ca2+ concentration were studied in left ventricular papillary muscles of normal and cardiomyopathic Syrian hamsters (SCH) from the UM-X 7.1 strain, both at the onset of myolysis (50-day-old animals) and at the cardiac hypertrophy stage (180-day-old animals) in the absence of congestive heart failure. A marked decrease in all indices of systolic performance was observed in 180-day-old myopathic hamsters as compared to age-matched controls. This was associated with (1) an impairment of the relaxation phase, (2) a loss of the load sensitivity of relaxation, and (3) a decrease in the inotropic and lusitropic responsiveness to Ca2+. On the other hand, when some indices of contraction and the inotropic response to Ca2+ were impaired in 50-day-old myopathic hamsters as compared to age-matched controls, relaxation phase and the lusitropic response to Ca2+ did not alter. This study shows that, in the UM-X 7.1 myopathic hamsters at the earlier stage of the disease, alterations in calcium homeostasis and contraction seem to be the first determinant factors of the development of heart failure when relaxation is not impaired. Conversely, when cardiac hypertrophy has developed, impaired relaxation may worsen heart failure.

[Restoring normal coronary reserve in treated hypertension without left ventricular hypertrophy]

It has been previously demonstrated that coronary vascular reserve (CVR) was severely impaired in hypertensive patients with left ventricular hypertrophy (LVH), even after anti-hypertensive therapy. To assess if CVR was similarly depressed in hypertensive patients without LVH, peak-to-resting coronary flow velocity ratio (P/R) and a minimal coronary vascular resistance index (MCVRI) were determined with a coronary Doppler catheter placed into the left anterior descending coronary artery and maximally vasodilating dose of intracoronary papaverine (12 mg) in 16 control subjects (C), 7 untreated hypertensives without LVH (G1), and 7 hypertensives without LVH treated for at least one year (G2). All subjects and patients had normal left ventricular angiography and coronary arteriography. Left ventricular and aortic pressures, rate-pressure-product (RPP) were significantly elevated in G1 and were similar to those of control subjects in G2. Results evidenced that P/R was reduced and that MCVRI was increased in G1. However, these alterations were moderate. In G2, these two indices were similar to those of control subjects: [table: see text]

CONCLUSIONS

These results suggest: 1) that alterations of coronary microcirculation occur before left ventricular hypertrophy in hypertensive patients; 2) that anti-hypertensive therapy may restore a normal coronary vascular reserve in hypertensive patients without LVH, when coronary vascular reserve remained severely impaired despite normalization of arterial pressure in patients with persistent LVH.

[Coronary reserve in treated hypertension with persistent left ventricular hypertrophy]

It has been demonstrated that coronary reserve (CR) is impaired in hypertensive patients with left ventricular hypertrophy and normal epicardial coronary arteries. The present study was undertaken in order to determine if CR returns to normal level after antihypertensive therapy in patients with persistent left ventricular hypertrophy, when the decrease of arterial blood pressure induces a reduction of LV wall stress (LVWS). In 26 patients with normal coronary arteriography, end-diastolic wall thickness (EDWT), LV mass (LVM) and peak systolic LVWS were determined on 30 degrees right anterior oblique LV angiography with simultaneous recording of LV pressure (micromanometer). Coronary flow velocity was measured with a coronary doppler catheter before and after a maximally vasodilating dose of intracoronary papaverine (12 mg). The study group included 6 untreated (G1) and 7 treated (G2) hypertensive patients with LV hypertrophy, and 13 control subjects (C). The peak-to-resting coronary flow velocity ratio (P/R) and a minimal coronary vascular resistance index (MCVRI) calculated as the quotient of mean aortic pressure at peak flow velocity to peak flow velocity and mean aortic pressure at resting flow velocity to resting flow velocity were assessed. Results evidenced that in hypertensive patients with LV hypertrophy, levels of P/R and MCVRI were similar in treated and untreated groups. Thus, in treated patients P/R remained lower and MCVRI remained higher than in control subjects despite the normalization of arterial pressure that resulted in a low peak systolic LVWS. [table: see text]

CONCLUSION

this study demonstrates that anti-hypertensive therapy does not restore a normal coronary vascular reserve in patients with persistent LV hypertrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

[Ventricular arrhythmia following thioridazine poisoning]

The authors report a case of acute thioridazine (Melleril) poisoning with manifestations of polymorphous ventricular rhythm disturbances in the form of torsades de pointes, with an impaired conscious level. The opportunity is taken to review the electrocardiographic changes and cardiac complications linked to the quinidine-like effect of Melleril.

[Unstable angina: from physiopathology to therapeutics]

Unstable angina is a term which encompasses several clinical syndromes (crescendo angina, angina de novo, resting angina, postinfarction angina), intermediary between stable angina and myocardial infarction. The results of coronary angioscopy have allowed differentiation of accelerated effort angina which seems related to ulceration of an atheromatous plaque from resting angina, more commonly associated with intraluminal thrombosis. The diagnosis of unstable angina is clinical and justifies immediate hospital admission to a coronary care unit because of the risk of myocardial infarction and/or sudden death. Medical management comprises triple anti-ischemic therapy (nitrate derivatives, betablockers, calcium antagonists), anticoagulants and platelet antiagregants. Randomised therapeutic trials versus placebo have shown that this treatment decreases the incidence of refractory angina and myocardial infarction. Several studies are under way to assess the role of thrombolytic therapy in unstable angina. When unstable angina is refractory to maximal medical therapy, emergency coronary angiography should be performed. However the outcome is usually favourable and coronary angiography can be performed several days after the acute event. The coronary lesion responsible for unstable angina is often "complex", an eccentric, irregular, severe stenosis or appearances of thrombosis. Whenever possible, depending on the coronary lesion, myocardial revascularisation by coronary angioplasty or aorto-coronary bypass should be proposed. Surgical treatment has been shown to be more effective (symptomatic relief, improved survival) than medical therapy in patients with triple vessel disease. However, the results of studies comparing medical or surgical treatment with coronary angioplasty are not yet available.

Coronary vasodilation induced by intracoronary enalaprilat: an argument for the role of a local renin-angiotensin system in patients with dilated cardiomyopathy

Although indicated by several experimental studies, the presence of a renin-angiotensin system has not been demonstrated in the human heart. The influence of a local renin-angiotensin system on the coronary vessels may be difficult to establish after oral or intravenous administration of an angiotensin converting-enzyme inhibitor, since coronary blood flow depends greatly on the loading conditions of the left ventricle. To avoid such a situation, our study consisted in a direct bilateral intracoronary infusion of enalaprilat in patients with dilated cardiomyopathy and normal coronary arteries (mean ejection fraction = 32 +/- 11%, n = 12). This intracoronary infusion (0.05 mg min-1, 1 ml min-1 in each coronary artery) resulted in no significant change of the systemic resistances (20.6 +/- 5.6 to 22.0 +/- 5.1 mmHg l-1 min), rate-pressure product (10,974 +/- 2630 to 10,214 +/- 2486) or myocardial oxygen consumption (21.08 +/- 6.37 to 22.10 +/- 6.42 ml min-1). Despite these steady haemodynamic conditions, intracoronary enalaprilat provoked a significant elevation of coronary sinus blood flow (181 +/- 73 to 214 +/- 79 ml min-1, P less than 0.001) with a reduction of coronary resistance (0.51 +/- 0.17 to 0.41 +/- 0.15 mmHg ml-1 min, P less than 0.001), and no significant alteration in plasma renin activity or plasma aldosterone. The results of this intracoronary infusion of enalaprilat demonstrate that this angiotensin converting-enzyme inhibitor has significant coronary vasodilator properties, which can be evidenced without stimulating the peripheral renin-angiotensin system.(ABSTRACT TRUNCATED AT 250 WORDS)

Reversibility by dipyridamole of thallium-201 myocardial scan defects in patients with sarcoidosis

PURPOSE

In order to clarify the significance of anginal pain and myocardial thallium-201 scan defects in cardiac sarcoidosis, the pharmacologic effect of dipyridamole on myocardial perfusion was assessed by planar thallium-201 myocardial scintigraphy in patients with sarcoidosis.

PATIENTS AND METHODS

Thallium-201 myocardial scintigraphy was performed at rest and after 0.56 mg/kg intravenous dipyridamole during four minutes in 16 patients with sarcoidosis. The myocardial scan (45-degree and 70-degree left anterior oblique, and anterior views) was divided into 15 segments. Results were evaluated by the number of segmental defects and with a global perfusion score (from 0 to 60) by a semi-quantitative index depending on the size and severity of myocardial thallium-201 defects.

RESULTS

Thirteen of the 16 patients showed partial or total reversion of their thallium-201 defects on redistribution scanning either at rest or after dipyridamole. The mean (+/- SD) number of myocardial perfusion defects that were present in all the patients decreased from 5.31 +/- 1.78 at rest to 3.25 +/- 2.52 after redistribution (p less than 0.001) and to 2.19 +/- 2.10 after dipyridamole (p less than 0.001). The mean global perfusion score increased from 53.2 +/- 3.0 at rest to 56.2 +/- 2.9 after redistribution (p less than 0.001) and to 57.2 +/- 2.7 after dipyridamole (p less than 0.001). A significant correlation (r = 0.82, p less than 0.001) was found between the increase of global perfusion score on redistribution and after dipyridamole.

CONCLUSION

The reversibility of myocardial scan defects is a common finding in sarcoidosis. It makes unlikely the role of scar fibrosis or extensive confluent granulomas as a mechanism for such defects. The effect of dipyridamole suggests the presence of reversible disorders lying at the coronary microvascular level.

Coronary flow and resistance reserve in patients with chronic aortic regurgitation, angina pectoris and normal coronary arteries

Left ventricular hypertrophy has been found to be associated with a reduction of coronary vascular reserve, which could be responsible for episodes of myocardial ischemia. To evaluate coronary flow and resistance reserve in patients with chronic aortic regurgitation, coronary sinus blood flow and coronary resistance were measured before and after an intravenous dipyridamole infusion (0.14 mg/kg per min X 4 min) in eight control subjects and eight patients with aortic regurgitation, exertional angina pectoris and normal coronary arteriograms. Coronary flow reserve, evaluated by the dipyridamole/basal coronary sinus blood flow ratio, and coronary resistance reserve, evaluated by the basal/dipyridamole coronary resistance ratio, were both significantly reduced in patients with aortic regurgitation (1.67 +/- 0.40 versus 4.03 +/- 0.52 in control subjects, p less than 0.001 and 1.71 +/- 0.50 versus 4.38 +/- 0.88 in control subjects, p less than 0.001, respectively). In patients with aortic regurgitation, basal coronary sinus blood flow was higher than in control subjects (276 +/- 81 versus 105 +/- 24 ml/min, respectively, p less than 0.001) and basal coronary resistance was lower (0.31 +/- 0.13 versus 0.95 +/- 0.17 mm Hg/ml per min, respectively, p less than 0.001), but coronary blood flow and resistance after dipyridamole were not significantly different in the two groups (461 +/- 159 versus 418 +/- 98 ml/min in control subjects, 0.19 +/- 0.11 versus 0.22 +/- 0.04 mm Hg/ml per min in control subjects, respectively). These data demonstrate that coronary reserve is severely reduced in patients with chronic aortic regurgitation and exertional angina.(ABSTRACT TRUNCATED AT 250 WORDS)