Nimesulide, a COX-2 inhibitor, sensitizes pancreatic cancer cells to TRAIL-induced apoptosis by promoting DR5 clustering †

Nimesulide is a nonsteroidal anti-inflammatory drug and a COX-2 inhibitor with antitumor and antiproliferative activities that induces apoptosis in oral, esophagus, breast, and pancreatic cancer cells. Despite being removed from the market due to hepatotoxicity, nimesulide is still an important research tool being used to develop new anticancer drugs. Multiple studies have been done to modify the nimesulide skeleton to develop more potent anticancer agents and related compounds are promising scaffolds for future development. As such, establishing a mechanism of action for nimesulide remains an important part of realizing its potential. Here, we show that nimesulide enhances TRAIL-induced apoptosis in resistant pancreatic cancer cells by promoting clustering of DR5 in the plasma membrane. In this way, nimesulide acts like a related compound, DuP-697, which sensitizes TRAIL-resistant colon cancer cells in a similar manner. Our approach applies a time-resolved FRET-based biosensor that monitors DR5 clustering and conformational states in the plasma membrane. We show that this tool can be used for future high-throughput screens to identify novel, nontoxic small molecule scaffolds to overcome TRAIL resistance in cancer cells.

Zafirlukast Is a Promising Scaffold for Selectively Inhibiting TNFR1 Signaling

Tumor necrosis factor (TNF) plays an important role in the pathogenesis of inflammatory and autoimmune diseases such as rheumatoid arthritis and Crohn's disease. The biological effects of TNF are mediated by binding to TNF receptors, TNF receptor 1 (TNFR1), or TNF receptor 2 (TNFR2), and this coupling makes TNFR1-specific inhibition by small-molecule therapies essential to avoid deleterious side effects. Recently, we engineered a time-resolved fluorescence resonance energy transfer biosensor for high-throughput screening of small molecules that modulate TNFR1 conformational states and identified zafirlukast as a compound that inhibits receptor activation, albeit at low potency. Here, we synthesized 16 analogues of zafirlukast and tested their potency and specificity for TNFR1 signaling. Using cell-based functional assays, we identified three analogues with significantly improved efficacy and potency, each of which induces a conformational change in the receptor (as measured by fluorescence resonance energy transfer (FRET) in cells). The best analogue decreased NF-κB activation by 2.2-fold, IκBα efficiency by 3.3-fold, and relative potency by two orders of magnitude. Importantly, we showed that the analogues do not block TNF binding to TNFR1 and that binding to the receptor's extracellular domain is strongly cooperative. Despite these improvements, the best candidate's maximum inhibition of NF-κB is only 63%, leaving room for further improvements to the zafirlukast scaffold to achieve full inhibition and prove its potential as a therapeutic lead. Interestingly, while we find that the analogues also bind to TNFR2 in vitro, they do not inhibit TNFR2 function in cells or cause any conformational changes upon binding. Thus, these lead compounds should also be used as reagents to study conformational-dependent activation of TNF receptors.

Discovery of a Non-competitive TNFR1 Antagonist Affibody with Picomolar Monovalent Potency That Does Not Affect TNFR2 Function

Tumor necrosis factor (TNF) is a key regulator of immune responses and plays a significant role in the initiation and maintenance of inflammation. Upregulation of TNF expression leads to several inflammatory diseases, such as Crohn's, ulcerative colitis, and rheumatoid arthritis. Despite the clinical success of anti-TNF treatments, the use of these therapies is limited because they can induce adverse side effects through inhibition of TNF biological activity, including blockade of TNF-induced immunosuppressive function of TNFR2. Using yeast display, we identified a synthetic affibody ligand (ABYTNFR1-1) with high binding affinity and specificity for TNFR1. Functional assays showed that the lead affibody potently inhibits TNF-induced NF-κB activation (IC50 of 0.23 nM) and, crucially, does not block the TNFR2 function. Additionally, ABYTNFR1-1 acts non-competitively─it does not block TNF binding or inhibit receptor-receptor interactions in pre-ligand-assembled dimers─thereby enhancing inhibitory robustness. The mechanism, monovalent potency, and affibody scaffold give this lead molecule uniquely strong potential as a therapeutic candidate for inflammatory diseases.

Cohort profile: the ESC EURObservational Research Programme Non-ST-segment elevation myocardial infraction (NSTEMI) Registry

AIMS

The European Society of Cardiology (ESC) EURObservational Research Programme (EORP) Non-ST-segment elevation myocardial infarction (NSTEMI) Registry aims to identify international patterns in NSTEMI management in clinical practice and outcomes against the 2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without ST-segment-elevation.

METHODS AND RESULTS

Consecutively hospitalised adult NSTEMI patients (n = 3620) were enrolled between 11 March 2019 and 6 March 2021, and individual patient data prospectively collected at 287 centres in 59 participating countries during a two-week enrolment period per centre. The registry collected data relating to baseline characteristics, major outcomes (in-hospital death, acute heart failure, cardiogenic shock, bleeding, stroke/transient ischaemic attack, and 30-day mortality) and guideline-recommended NSTEMI care interventions: electrocardiogram pre- or in-hospital, pre-hospitalization receipt of aspirin, echocardiography, coronary angiography, referral to cardiac rehabilitation, smoking cessation advice, dietary advice, and prescription on discharge of aspirin, P2Y12 inhibition, angiotensin converting enzyme inhibitor (ACEi)/angiotensin receptor blocker (ARB), beta-blocker, and statin.

CONCLUSION

The EORP NSTEMI Registry is an international, prospective registry of care and outcomes of patients treated for NSTEMI, which will provide unique insights into the contemporary management of hospitalised NSTEMI patients, compliance with ESC 2015 NSTEMI Guidelines, and identify potential barriers to optimal management of this common clinical presentation associated with significant morbidity and mortality.

Massive right atrial myxoma causing exertional dyspnoea

Metastatic tumours are the commonest cardiac tumours being found in 1-3% of patients dying of cancer while primary tumours are unusual and have an incidence of 0.02-0.5%. The majority (80%) of all primary cardiac tumours are benign with myxomas accounting for 50%. Myxomas arising from the right atrium are uncommon. We present the case of a 39-year-old female with a 4-month history of progressive exertional dyspnoea accompanied by symptoms of palpitations and presyncope. Transthoracic echocardiography showed an extremely large right atrial myxoma prolapsing into the right ventricle and obstructing the tricuspid valve. We demonstrate how intraoperative transoesophageal echocardiography, prior to sternotomy, was useful in providing information about the myxoma which clearly displayed its attachment and anatomical relationship in the planning of the 'safe' surgical excision.

Early experience with a helical coronary thrombectomy device in patients with acute coronary thrombosis

OBJECTIVE

To report our experience with a new thrombectomy device (X-SIZER(TM)) in patients with angiographically visible thrombus or total coronary occlusion in the setting of acute coronary syndromes.

DESIGN

A safety and feasibility study in the use of the X-SIZER during intervention in patients with acute coronary syndromes.

PATIENTS

35 patients, age range 31 to 83 years (mean 60).

SETTING

University Hospitals of Coventry and Warwickshire NHS Trust (tertiary referral centre).

INTERVENTIONS

The indication for intervention was primary or salvage percutaneous coronary intervention for acute myocardial infarction in 17 of the 35 patients; unstable angina or non-ST-elevation myocardial infarction in 10; and unstable postinfarct angina in eight. Abciximab was given in 11 patients.

MAIN OUTCOME MEASURES

Device success (successful deployment of the device at the site of the lesion with resultant improvement in TIMI flow); clinical success (no residual stenosis at the end of the procedure with no in-hospital major adverse coronary events).

RESULTS

Successful use of the device was achieved in 26 of the 35 cases. It failed to cross the lesion in five and failed to improve TIMI flow despite crossing the lesion in four. Clinical success was achieved in 30 of the 35 cases. Device related complications occurred in two cases (vessel perforation) and there was one intraprocedural death (acute myocardial infarction with cardiogenic shock).

CONCLUSIONS

Thrombectomy with the X-SIZER catheter system appears promising in percutaneous coronary intervention where thrombus extraction is considered necessary before stent implantation.

Evaluation of patient characteristics and utilisation of invasive cardiac procedures in a UK ethnic population with unstable angina pectoris

OBJECTIVES

To evaluate patient characteristics and utilisation of invasive cardiac procedures in a UK ethnic population with unstable angina pectoris (UAP).

DESIGN

Retrospective, observational study.

SETTING

Tertiary referral cardiology centre in the United Kingdom serving a large Asian ethnic population.

SUBJECTS

White and Asian patients undergoing PTCA for UAP over a 2.5-year period at a UK referral cardiology centre from a comprehensive PTCA database. Data were also collated for all emergency admissions with unstable angina, or angina (type unspecified), to our institute.

MAIN OUTCOME MEASURES

Demographic and angiographic characteristics of patients undergoing PTCA. Frequency of usage of invasive cardiac procedures was determined in emergency angina admissions.

RESULTS

From January 1997 to July 1999, 435 White and 36 Asian patients underwent PTCA for UAP at our institute. Asian patients were on average 4.4 years younger (P=0.015), had 19.3% more diabetes (P=0.003) and 19.7% less smoking (P=0.007). Trends to more single vessel disease in Whites and more double vessel disease in Asians were observed, with similar rates of triple vessel disease. Interestingly, Asians also had trends towards more left-sided coronary artery disease and revascularisation, smaller vessels and less bail-out stenting. Asian patients were significantly less likely to undergo coronary angiography, OR 0.64 (CI 0.45-0.91, P=0.012), during the index admission, and showed a trend to less PTCA.

CONCLUSIONS

Asian patients with unstable angina pectoris appear to have clinical and angiographic differences from their White counterparts, and are less likely to have invasive cardiac procedures deployed. The reasons for these observations require elucidation and the prognostic significance of these findings is uncertain.

Multiple coronary aneurysms in a patient with neurofibromatosis type 1: case report and intravascular ultrasound of aneurysm

A 54 year old woman with neurofibromatosis type 1 (NF-1) was found to have multiple coronary aneurysms. Intraoperative intravascular ultrasound (IVUS) revealed severe coronary disease proximal to the aneurysm that had not been apparent angiographically. An IVUS picture of one of the giant coronary aneurysms is also shown. The vascular manifestations of neurofibromatosis and the causes of coronary aneurysms are reviewed.

Coronary artery stenting in unstable angina pectoris: a comparison with stable angina pectoris

OBJECTIVE

To compare early complication rates in unselected cases of coronary artery stenting in patients with stable v unstable angina.

SETTING

Tertiary referral centre.

PATIENTS

390 patients with stable angina pectoris (SAP) and 306 with unstable angina (UAP). Patients treated for acute myocardial infarction (primary angioplasty) or cardiogenic shock were excluded.

INTERVENTIONS

268 coronary stents were attempted in 211 patients (30.3%). Stents used included AVE (63%), Freedom (14%), NIR (7%), Palmaz-Schatz (5%), JO (5%), and Multilink (4%). Intravascular ultrasound was not used in any of the cases. All stented patients were treated with ticlopidine and aspirin together with periprocedural unfractionated heparin.

RESULTS

123 stents were successfully deployed in 99 SAP patients v 132 stents in 103 UAP patients. Failed deployment occurred with nine stents in SAP patients, v four in UAP patients (NS). Stent thrombosis occurred in four SAP patients and 11 UAP patients. Multivariate analysis showed no relation between stent thrombosis and clinical presentation (SAP v UAP), age, sex, target vessel, stent length, or make of stent. Stent thrombosis was associated with small vessel size (p < 0.001) and bailout stenting (p = 0.01) compared with elective stenting and stenting for suboptimal PTCA, with strong trends toward smaller stent diameter (p = 0.052) and number of stents deployed (p = 0.06). Most stent thromboses occurred in vessels < 3 mm diameter.

CONCLUSIONS

Coronary artery stenting in unstable angina is safe in vessels >/= 3 mm diameter, with comparable initial success and stent thrombosis rates to stenting in stable angina.

Intravascular monitoring of successful reperfusion following rescue angioplasty

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An ominous complication of acute myocardial infarction

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Coronary ventricular fistula as a complication of PTCA: a case report and literature review

A 58-year-old man with previous myocardial infarction and coronary bypass surgery underwent angioplasty to a totally occluded venous graft to the left anterior descending artery (LAD). The procedure resulted in a coronary-ventricular fistula. Prolonged inflation of the balloon in the proximal part of the graft resulted in obliteration of the fistula with little haemodynamic compromise.

The occurrence of early sudden coronary artery occlusion following angioplasty may be predicted from the clinical characteristics of the patients and their coronary lesion morphology

The aim of this study was to assess whether the incidence of early occlusion following angioplasty was greater among patients with unstable angina and whether the coronary lesions prone to early occlusion could be predicted from their angiographic appearance. Seventy-seven patients who had had a first angioplasty of a native vessel for stable or unstable angina in one twelve month period were included. The angiographic appearances of the angioplastied lesions were classified as either Type 1, which were smooth and unlikely to have thrombus or intimal rupture, or Type 2, which were irregular due to thrombus or intimal rupture. The lesion classification was compared to the patients' clinical features, i.e. stable or unstable angina, and the outcome of the angioplasty. Type 2 lesions occurred in 25% of patients with stable angina but 49% of patients with unstable angina (p less than 0.05). Early sudden occlusion of the angioplastied vessel occurred in 24% of patients with unstable angina but in only 3% of patients with stable angina (p less than 0.05) and in 6% of Type 1 lesions compared with 24% of Type 2 lesions (p less than 0.05). Thus it is possible to identify the clinical characteristics and angiographic appearances of those patients undergoing angioplasty who are most likely to experience early vessel occlusion.

Reduction in ST segment elevation after thrombolysis predicts either coronary reperfusion or preservation of left ventricular function

The usefulness of a reduction in ST segment elevation to predict coronary reperfusion in myocardial infarction remains uncertain. ST segment changes and angiographic findings were compared in 45 patients soon after thrombolysis. The percentage ST segment change 3 hours after treatment (in the lead showing the greatest initial ST elevation) was compared with the TIMI perfusion grade (thrombolysis in myocardial infarction trial) obtained between 90 minutes and 3 hours after treatment. Global ejection fraction and regional wall motion were assessed by cineventriculography (11 (5) days (mean (SD))) and by gated blood pool imaging (44 (11) days). Prediction of coronary patency by a reduction of greater than 25% in ST segment elevation 3 hours after thrombolytic treatment had a sensitivity of 97% but a specificity of only 43%. Where the ST segment elevation was reduced by greater than 25% the global ejection fraction was well maintained whether or not the infarct vessel was patent. In patients with a reduction of less than 25% in ST elevation, the ejection fraction was significantly lower and regional wall motion abnormality more severe. Reduction in ST elevation of greater than 25% within 3 hours of thrombolysis indicates either a patent infarct artery or preservation of left ventricular function. When the ST segment elevation does not fall by greater than 25% persistent coronary occlusion is likely (predictive accuracy 86%) and is associated with a lower ejection fraction. These patients may benefit from further treatment or additional interventions.

Valvar stenosis: a comparison of clinical assessment, echocardiography, Doppler ultrasound and catheterisation

The relative merits of noninvasive techniques in the assessment of valve stenosis were examined by comparing the results of clinical assessment by two independent clinicians, the cross-sectional echocardiogram and Doppler ultrasound using the results of cardiac catheterisation as reference in 58 patients with a total of 60 stenotic valve lesions. Doppler ultrasound was the most reliable technique; it was correct in 57 (95%) of the 60 lesions. Clinical assessment and cross sectional echocardiography were correct in 48 (80%), and 46 (77%) of the 60 lesions, respectively. In 7 instances 2 noninvasive assessments were wrong in the same patient but on no occasion were all 3 techniques misleading in the same patient. In 17 patients with severe mitral stenosis, clinical assessment Doppler ultrasound and cross-sectional echocardiography were correct in 14 (82%), 16 (94%) and 17 (100%) patients, respectively, whilst in the 4 patients with moderate mitral stenosis the corresponding figures were 3 (75%), 4 (100%) and 2 (50%). In mild mitral stenosis (3 patients), the clinical assessment was correct in 2 (67%) patients, Doppler ultrasound in 3 (100%) patients and cross-sectional echocardiography in 2 (67%) patients. In 22 patients with severe aortic stenosis, the clinical assessment and Doppler ultrasound were correct in every patient (100%), whilst the cross-sectional echocardiogram was correct in 18 (82%) patients. In 11 patients with moderate aortic stenosis, the clinical assessment was correct in only 5 (45%) patients, the cross-sectional echocardiogram in 5 (45%) patients and Doppler assessment in 9 (82%) patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Serial angiographic findings during the development of a saccular aneurysm of the coronary artery in association with unstable angina

A 60 year old man presented with unstable angina and electrocardiographic features suggestive of disease of the left anterior descending coronary artery. Angiography showed slight proximal narrowing in this artery with reduced density of contrast that suggested an associated thrombus. Repeat angiography after 24 hours of heparin administration showed the development of a small saccular aneurysm. Three weeks later, after a further episode of unstable angina, angiography showed enlargement of the aneurysm. Although there were no further episodes of angina, repeat angiography three months after the initial event showed further slight enlargement of the aneurysm. It is suggested that the episodes of angina at rest were secondary to embolisation of thrombotic or atheromatous material or both.

Pacemaker twiddler: a twist in the tail?

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Myocardial involvement in systemic lupus erythematosus detected by magnetic resonance imaging

Myocardial involvement in systemic lupus erythematosus is commonly found at autopsy but seldom recognized clinically or by routine cardiological investigations. As the magnetic resonance relaxation parameter, T1, is altered by changes in tissue cellularity, we carried out magnetic resonance imaging in 10 patients with systemic lupus erythematosus. Five had active systemic lupus erythematosus when assessed using the lupus activity criteria count. The mean (+/- SD) T1 was 319 +/- 12 in normal volunteers and 321 +/- 10 in a second control group with hypertrophic cardiomyopathy. In the group with systemic lupus erythematosus, there was a higher mean value of 336 ms with a wider scatter of individual results (SD +/- 22 ms). In the subgroup of patients with active disease, T1 was significantly higher (349 +/- 24) than in either of the two control groups. In addition, there was an inverse correlation between serum complement and myocardial T1 in patients with systemic lupus erythematosus. Myocardial abnormalities in systemic lupus erythematosus were demonstrated by magnetic resonance imaging even where other non-invasive cardiac investigations were negative. We conclude that T1 calculated from magnetic resonance imaging is often abnormal in systemic lupus erythematosus and probably indicates myocardial involvement.

Congenital left atrial wall aneurysm in a patient with neurofibromatosis

A congenital intrapericardial aneurysmal dilatation of the left atrial wall was found in a 28 year old man who presented with atrial fibrillation after a syncopal event. The patient had cutaneous manifestations of neurofibromatosis. The diagnosis was made by cross sectional echocardiography and confirmed by angiocardiography. Surgical excision of the aneurysm resolved the symptoms.

Serial changes in the T1 magnetic relaxation parameter after myocardial infarction in man

A low field resistive nuclear magnetic resonance imaging system (0.08 Tesla) was used to study the in vivo changes in the relaxation parameter T1 of the left ventricular myocardium from the first day to six months after acute myocardial infarction in 41 consecutive patients admitted to a coronary care unit. T1 maps were constructed from transverse and coronal images at various times after infarction. Thrombolytic treatment had been successful in 28 patients. Thirty three of the 34 patients studied within two weeks of infarction had a significantly increased T1 value but this developed only after the third day in four. At day 1-3 the mean (1 SD) maximum T1 was 413 (29) ms (n = 23) compared with 430 (41) ms (n = 22) at day 4-7, 433 (35) ms (n = 24) at day 8-14, 420 (34) at one month (n = 22), 388 (39) (n = 20) at three months, and 361 (24) (n = 14) at six months. The number of regions of interest with an increased T1 followed a similar time course. Although the increase in T1 measured at three months correlated with the initial maximum creatine kinase and with the left ventricular ejection fraction measured at one month, the number of regions with abnormal T1 from day 4 through to one month correlated best with left ventricular ejection fraction. There was no significant difference in T1 between patients with or without reperfusion. The rise in T1 over the first few days together with the prolonged time course of T1 increase suggests that the increase in T1 may reflect cellular infiltration as much or more than tissue oedema.

Left ventricular function after anisoylated plasminogen streptokinase activator complex

Limitation of the reduction in left ventricular function after acute myocardial infarction is an important indicator of benefit following thrombolytic therapy. Therefore, left ventricular function was studied by radionuclide ventriculography in 91 patients entering 3 separate studies of anisoylated plasminogen streptokinase activator complex (APSAC) administered within 4 hours of acute myocardial infarction. Global left ventricular ejection fraction was measured at 10 days and at 6 months to assess early and late effects of therapy, with particular emphasis on the timing of treatment and the site of infarction. Successful therapy with APSAC in anterior infarction resulted in preservation of left ventricular function at 10 days. The magnitude of benefit declined with increasing symptom duration before treatment, and was maintained at 6 months in those patients without reocclusion. The benefit of successful therapy was less marked in the inferior infarct group at 10 days. By 6 months, no significant benefit was detected because of an increase in ejection fraction in the placebo and occlusion or reocclusion group with inferior infarction. Early therapy results in greater preservation of left ventricular function, and recovery of function may be more rapid than with later treatment. More emphasis on early administration of thrombolytic therapy is indicated.

Effect of the specific thromboxane receptor blocking drug AH23848 in patients with angina pectoris

The effect of the specific thromboxane receptor blocking drug AH23848 was investigated in two double blind placebo controlled studies in male patients with exercise induced angina pectoris and angiographically verified coronary lesions. In the first study cardiac pacing was performed in twenty patients after coronary angiography. Patients were then randomised into two groups and received either AH23848 (70 mg orally) or placebo. One hour later cardiac pacing was repeated. Neither treatment had any significant effect upon time to angina or the rate-pressure product at the onset of chest pain in these patients. In the second study twenty male patients were randomised to seven days' treatment with AH23848 (70 mg three times a day) or placebo followed by a crossover to the other treatment for a further seven days. Clinical assessment was performed before treatment and at the end of each treatment period. There was no significant difference between the placebo and AH23848 treatment periods in exercise tolerance, the rate-pressure product at angina after exercise testing, the number of ischaemic attacks as determined from 24 hour ambulatory electrocardiograms, the number of attacks of pain, or the number of glyceryl trinitrate tablets consumed. This lack of a clinical effect with AH23848 was seen despite a profound inhibition of ex vivo platelet aggregation stimulated by the thromboxane A2-mimetic U-46619. Because in experimental animals in vivo AH23848 blocks vascular thromboxane receptors as well as platelet thromboxane receptors the lack of effect of AH23848 in cardiac pacing and exercise induced angina is unlikely to be the result of inadequate blockade of thromboxane receptors. The lack of effect of the drug is more likely to indicate that thromboxane A2, is not a factor in the aetiology of the pain experienced by these patients during exercise or cardiac pacing.

Clinical effects and kinetic properties of intravenous APSAC--anisoylated plasminogen-streptokinase activator complex (BRL 26921) in acute myocardial infarction

Fifty patients with a first myocardial infarction presenting within 4 hours of the onset of symptoms were treated with intravenous anisoylated plasminogen-streptokinase activator complex (APSAC-BRL 26921). Vessel patency with good flow was documented in 88%. The left ventricular ejection fraction declined with the duration of symptoms before treatment (r = -0.53, P less than 0.001). The correlation persisted for the group with anterior infarction (r = -0.46, P less than 0.05) where the mean left ventricular ejection fraction prior to discharge from hospital was 36 +/- 9% compared to 49 +/- 7% for the group with inferior infarction. Reinfarction developed in 12% and mortality at 6 months for the whole group was 6%. A degree of systemic fibrinolysis did occur with a fall in mean plasma fibrinogen from 3.20 g/l to 1.08 g/l. A pharmacokinetic study was performed in six patients demonstrating a clearance half-life of fibrinolytic activity of 87.5 +/- 5.0 min. APSAC is an effective intravenous thrombolytic agent with a relatively long half-life of fibrinolytic activity.

Intracoronary thrombolytic therapy performed within a coronary care unit: one year's experience

Acute myocardial infarction is associated with a high incidence of occluding coronary arterial thrombi. Thrombolytic therapy has been advocated to restore coronary artery blood flow and to reduce myocardial damage. Coronary arteriography and intracoronary thrombolytic therapy was administered to 61 patients admitted to a Coronary Care Unit within eight hours of symptoms. Successful reperfusion was obtained in 38 of 46 single vessel occlusions associated with a first coronary attack. Failure of reperfusion occurred in patients with two vessel occlusions or with cardiogenic shock. This study demonstrates the feasibility of applying this technique within a Coronary Care Unit with low capital and running costs, and suggests that its widespread application is possible even within the setting of a District General Hospital.

Characterisation of acute myocardial infarction by gated magnetic resonance imaging

In studies with gated nuclear magnetic resonance imaging, patients with recent transmural myocardial infarction showed significantly longer spin-lattice relaxation times (T1) in the infarct area than did healthy volunteers or patients with non-ischaemic or chronic ischaemic heart disease. 10 of the 13 patients had a T1 longer than that found in any healthy subject or in any patient with other heart disease. Changes in T1 should prove useful in the assessment of interventions designed to limit infarct size.

Nuclear magnetic resonance in hypertrophic cardiomyopathy

The large differences in the spin lattice relaxation times (T1) of blood and myocardium (measured by nuclear magnetic resonance) allow the heart to be visualised without the use of contrast media. The findings using nuclear magnetic resonance in 11 unselected patients with hypertrophic cardiomyopathy were compared with those in equal numbers of normal subjects and patients with electrocardiographic features of left ventricular hypertrophy. In patients with hypertrophic cardiomyopathy characteristic septal hypertrophy was noted together with variable and sometimes pronounced hypertrophy of the left ventricular free wall, which is consistent with the heterogeneous nature of this disease. The mean (SD) ratio of septal to free wall thickness was 1.5(0.8) for patients with hypertrophic cardiomyopathy, 0.8(0.2) for those with left ventricular hypertrophy, and 0.9(0.2) for normal subjects. Although septal measurements by nuclear magnetic resonance were greater than those obtained by echocardiography there was a significant correlation between the two. Septal and free wall area were significantly smaller in normal subjects. There were no differences in septal or free wall T1 values between the three groups. Non-gated nuclear magnetic resonance can detect septal and free wall hypertrophy. With the addition of multiple slice acquisition, rapid estimation of myocardial mass will be possible allowing the potentially important assessment of progression or regression of myocardial hypertrophy.

Preoperative prediction of prosthesis size using cross sectional echocardiography in patients requiring aortic valve replacement

In 43 patients who underwent aortic valve replacement for aortic stenosis with or without regurgitation the accuracy of preoperative left ventricular angiography, parasternal long axis cross sectional echocardiography of left ventricular outflow tract and proximal ascending aorta, and M mode echocardiography of aortic root in predicting aortic root size and thereby prosthesis size was compared. Cross sectional echocardiographic measurements and angiographic measurements of aortic root correlated well with prosthesis size, with over two thirds of the indirect measurements being within 2 mm of prosthesis diameter. M mode echocardiography did not yield useful predictive information. Non-invasive preoperative evaluation of patients likely to require aortic valve replacement may be usefully extended to include aortic root dimensions measured by cross sectional echocardiography.

Coronary thrombolysis with intravenous anisoylated plasminogen-streptokinase complex BRL 26921

BRL 26921 is a protected plasminogen-streptokinase complex with selective affinity for thrombus. When given intravenously within three hours of the onset of a first acute myocardial infarction angiographic patency of the infarct related vessel was seen in all 16 patients receiving the active drug compared with only two of 16 receiving a placebo. There was relative sparing of left ventricular function in the active treatment group with anterior infarction (mean left ventricular ejection fraction 37% compared with 23% for placebo), but no significant difference in left ventricular function between the active and placebo groups was seen in patients with inferior infarction. Intravenous BRL 26921 is highly effective in causing coronary reperfusion and may help to preserve left ventricular function when given early in the course of anterior infarction.

Electrophysiological effects of felodipine in combination with metoprolol

The combined use of some beta-adrenoceptor blocking agents with calcium channel blockers may cause adverse pharmacodynamic drug interactions: hypotension, heart block or even asystole may be precipitated. The electrophysiological effects of combined administration of intravenous metoprolol 10mg and the vasodilating calcium antagonist felodipine (0.1 mg/kg/bodyweight) were assessed in an open study by invasive methods. Following metoprolol, the heart rate was reduced from 69 +/- 24 to 60 +/- 16 beats/min (mean +/- SD, p less than 0.05) with a minor prolongation of the sinus node recovery time. The A-H interval was increased from 94 +/- 25 to 109 +/- 16 msec (p less than 0.005) and the H-V interval was unchanged. The effective refractory period of the atrioventricular node was prolonged from 327 +/- 54 to 361 +/- 62 msec (p less than 0.01) with a minor prolongation of the effective refractory period of the ventricular Purkinje fibres. Systolic and diastolic blood pressures showed a mean reduction of 11 (p less than 0.001) and 6mm Hg (p less than 0.05), respectively. Following felodipine, the changes in heart rate and effective refractory periods of the atrioventricular node and ventricular Purkinje fibres returned towards control values. No further prolongation of the A-H interval resulted and further blood pressure changes were minor. The absence of adverse haemodynamic or electrophysiological effects suggests that this combination of agents may be safely used.

Electrophysiological effects of felodipine

Oral felodipine (10mg) was given to 11 patients undergoing routine invasive electrophysiological studies. Systolic blood pressure fell by 31 mm Hg from 130 +/- 17.5 to 99 +/- 10 mm Hg (mean +/- SD, p less than 0.001) while diastolic pressure fell from 78 +/- 9 to 60 +/- 8mm Hg (p less than 0.001), thus confirming its vasodilator properties. Heart increased from 64 +/- 10 to 78 +/- 16 beats/min (p less than 0.001). The A-H interval was significantly prolonged from 97 +/- 14 to 110 +/- 24 msec (p less than 0.01) while there was no change in the H-V interval. Sinus node recovery time showed no change when corrected for heart rate. The effective refractory period of the atrioventricular node was shortened from 317 +/- 38 to 287 +/- 27 msec (p less than 0.01) as was the effective refractory period of the ventricular Purkinje fibres from 251 +/- 18 to 237 +/- 20 msec (p less than 0.005). These haemodynamic and electrophysiological changes suggest that this compound is an effective vasodilator and may have potential antiarrhythmic properties.

Effect of afterload reduction in patients with ventricular and physiological pacing

The effect of afterload reduction was studied in a group of patients who remained breathless or tired after permanent ventricular pacing. Haemodynamic measurements were made before and after giving hydralazine 20 mg intravenously using a triple lumen thermodilution catheter and cuff blood pressure recordings during ventricular pacing at the standard rate of 71/min or an increased rate of 88/min and physiological pacing. Increasing the ventricular pacing rate had no effect on cardiac output as stroke volume fell. Hydralazine produced a greater rise in cardiac output than physiological pacing alone, although peak values were obtained by combining the two. Ventricular pacing produced intermittent large left and right atrial pressure peaks. Physiological pacing produced no such peaks, and mean right and left atrial pressures fell. Hydralazine did not significantly alter atrial pressures. These findings show that in these patients, most of whom had a low cardiac output, afterload reduction with ventricular pacing increased resting cardiac output more than physiological pacing alone. Nevertheless, persistence of high filling pressures despite afterload reduction may limit the potential therapeutic benefit. Care should be taken in extrapolating these data to other patient groups.