Prevention of contrast-induced nephropathy with urine alkalinization: the TEATE study

Background

Contrast-induced acute kidney injury (CI-AKI) after coronary angiography and percutaneous interventions (PCI) impacts on hospitalization duration and mortality. Pre-procedural hydration is the sole strategy currently recommended for preventing CI-AKI. The role of sodium bicarbonate (SB) although attractive, since urine alkalinization suppresses the production of reactive oxygen species, is still controversial, and the optimal dosing to attain adequate urine alkalinization is still undefined.

Purpose

The PrevenTion of contrast-inducEd nephropathy with urine alkalinization (TEATE) study was a prospective 3-center 3-arm single-blind randomized controlled trial testing the hypothesis that adequate urine alkalinization is associated with CI-AKI prevention. Secondary endpoints were the efficacy of SB vs saline in achieving adequate urine alkalinization and reducing the incidence of CI-AKI compared with saline.

Methods

Patients candidate to coronary angiography and/or PCI with moderate-to-severe chronic kidney disease [eGFR of 15 to 60 mL/min/1.73 m2, by the Modification of Diet in Renal Disease Study equation (MDRD)] were randomly assigned to saline hydration (control), oral SB or i.v. SB. The study protocol was registered. We evaluated urinary pH at the time of hospitalization, immediately before coronary angiography and 24–48 hours after angiography. According to urine pH immediately before the procedure, patients were divided in two groups above or below a pH cut-off of 6.

Results

We enrolled a total of 241 patients: 81 were randomly assigned to the control group, 82 to i.v. SB and 78 to oral SB. Patients achieving a urinary pH >6 before angiography had a lower incidence of CI-AKI (46%) than patients with urinary pH ≤6 (54%) [OR=0.48 (95% CI 0.25–0.9) p=0.023]. The number of patients with urine pH >6 was higher in both the i.v. (71%) and the oral SB (65%) groups compared to the hydration-only group (44%, p=0.004). We found however no difference in the incidence of CI-AKI in the 3 treatment arms (20% in hydration alone, 21% in oral SB group and 22% in iv SB group) (p=0.94). Subgroup analyses according to basal urine pH and eGFR ranges failed to identify statistically significant differences in the development of CI-AKI according to treatment allocation.

Conclusions

Urinary pH before the administration of contrast medium is an inverse correlate of CI-AKI incidence, and SB is superior to hydration alone in achieving urinary alkalinization. Since, however, SB did not reduce the incidence of CI-AKI, we conclude that urinary pH is a marker and not a mediator of CI-AKI.

Funding Acknowledgement

Type of funding sources: None.

Ticagrelor and preconditioning in patients with stable coronary artery disease (TAPER-S): a randomized pilot clinical trial

Background

Ticagrelor is a reversibly binding, direct-acting, oral, P₂Y₁₂ antagonist used for the prevention of atherothrombotic events in patients with coronary artery disease (CAD). Ticagrelor blocks adenosine reuptake through the inhibition of equilibrative nucleoside transporter 1 (ENT-1) on erythrocytes and platelets, thereby facilitating adenosine-induced physiological responses such as an increase in coronary blood flow velocity. Meanwhile, adenosine plays an important role in triggering ischemic preconditioning through the activation of the A1 receptor. Therefore, an increase in ticagrelor-enhanced adenosine bioavailability may confer beneficial effects through mechanisms related to preconditioning activation and improvement of coronary microvascular dysfunction.

Methods

To determine whether ticagrelor can trigger ischemic preconditioning and influence microvascular function, we designed this prospective, open-label, pilot study that enrolled patients with stable multivessel CAD requiring staged, fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI). Participants will be randomized in 1:1 ratios either to ticagrelor (loading dose (LD) 180 mg, maintenance dose (MD) 90 mg bid) or to clopidogrel (LD 600 mg, MD 75 mg) from 3 to 1 days before the scheduled PCI. The PCI operators will be blinded to the randomization arm. The primary endpoint is the delta (difference) between ST segment elevations (in millimeters, mm) as assessed by intracoronary electrocardiogram (ECG) during the two-step sequential coronary balloon inflation in the culprit vessel. Secondary endpoints are 1) changes in coronary flow reserve (CFR), index of microvascular resistance (IMR), and FFR measured in the culprit vessel and reference vessel at the end of PCI, and 2) angina score during inflations. This study started in 2018 with the aim of enrolling 100 patients. Based on the rate of negative FFR up to 30% and a drop-out rate up to 10%, we expect to detect an absolute difference of 4 mm among the study arms in the mean change of ST elevation following repeated balloon inflations. All study procedures were reviewed and approved by the Ethical Committee of the Catholic University of Sacred Heart.

Discussion

Ticagrelor might improve ischemia tolerance and microvascular function compared to clopidogrel, and these effects might translate to better long-term clinical outcomes.

Trial registration

EudraCT No. 2016–004746-28. No. NCT02701140. 

Trial status

Information provided in this manuscript refers to the definitive version (n. 3.0) of the study protocol, dated 31 October 2017, and includes all protocol amendments. Recruitment started on 18 September 2018 and is currently ongoing. The enrollment is expected to be completed by the end of 2019.

Trial sponsor

Fondazione Policlinico Universitario A. Gemelli – Roma, Polo di Scienze Cardiovascolari e Toraciche, Largo Agostino Gemelli 8, 00168 Rome, Italy.

P4642Prevalence and clinical significancy of bicuspid aortic valve diagnosed in the first year of life: a long term follow up in the paediatric age

Introduction and objectives

Bicuspid aortic valve (BAV) is the most common congenital malformation, with an estimated prevalence ranging from 0,48 to 2%. Most of the studies describe complications associated with BAV, including aortic stenosis and regurgitation, infective endocarditis and aortic dilation and dissection. Very few studies have been performed in the neonatal and paediatric age, most lacking in long-term follow up. The aim of our study was to explore the prevalence of BAV and the progression of aortic valve disease and aortic dilation in paediatric patients followed from January 1996 to August 2018.

Methods

A prospective collection of Congenital Heart Disease (CHD) diagnosed in the first year of life was performed in our institution from January 1996 to August 2018. Patients affected by BAV were then followed yearly. BAV morphology, aortic valve dysfunction and aortic dimensions were measured. Comparisons were performed between right-left cusp fusion (R-L) and right-non coronary cusp fusion (R-N), according to Shaefer's classification. Rate of change of the ascending aorta size over time was analyzed, and aortic size values were normalized as the number of standard deviations above or below the mean size expected for body surface area (z scores).

Results

A total of 35,310 live births were screened. Incidence rate of total CHD, including small ventricular septal defects and BAV was19,57%. Sixty had BAV (8,73% of CHD), with an incidence of 17/1,000 live births. Male/Female ratio was 1.4. A positive family history was present in 5 (8.3%). In 12 patients (24%) BAV was associated to other CHD (9 Aortic Coarctation, 1 Atrio-Ventricular Septal Defect, and in two cases a critical neonatal aortic stenosis). BAV was isolated in 48 cases (80%), with an incidence of 13.6/1.000 live births. According to Shaefer's classification the most common was type 1 (R-L), with Right to Left cusps fusion (R-L 76%, R-N 21% and L-N 3%). Among patients with isolated BAV, after a median follow up of 11 [1–21] years an aortic stenosis was observed in 5 patients (10.4%, none severe), an aortic insufficiency in 13 (27%, in one case severe). A dilated ascending aorta (z-score>2) was found in 11 patients (23%). An indication cardiac surgery due to severe aortic insufficiency was present in one case. No patient had indication for aortic aneurysm surgery.

Conclusions

Paediatric patients with isolated BAV warrant medical follow-up but progression towards severe valve dysfunction and/or dilation of the ascending aorta warranting cardiac surgery is very low.

Bivalirudin use in patients undergoing percutaneous coronary intervention for acute myocardial infarction. Insights from the prospective, multi-centre EUROVISION registry

BACKGROUND

The effectiveness of bivalirudin in patients undergoing percutaneous coronary intervention for acute myocardial infarction has been tested in clinical trials, but its use in a real-world scenario has never been reported.

METHODS

From the total number of patients enrolled in the EUROVISION registry, 678 subjects affected by ST-elevation myocardial infarction were selected and included in the analysis. Posology and usage patterns of bivalirudin, as evaluated by dose and time of drug bolus and infusion administered, were evaluated. The 30-day outcome has been assessed by efficacy and safety endpoints.

RESULTS

All patients received an initial intravenous bolus of bivalirudin (0.70±0.25 mg/kg) followed by an infusion (1.58±0.47 mg/kg/h; duration: 60 [30, 107] min) in 99.3% of cases. An additional bolus (0.49±0.06 mg/kg) was administered in 9.3% of patients. Bivalirudin infusion was prolonged after procedure in 62.2%. Death occurred in 2.1% of patients, non-fatal myocardial reinfarction in 0.3%, unplanned revascularization in 0.6% and non-fatal stroke in 0.4%. Acute stent thrombosis was not observed. Major bleeding occurred in 1.5% of patients.

CONCLUSIONS

Bivalirudin usage in the setting of primary PCI provided excellent results in terms of 30-day outcome even in a real-world population.

Effects of abciximab on microvascular integrity and left ventricular functional recovery in patients with acute infarction treated by primary coronary angioplasty

AIM

To investigate the effect of abciximab on microvascular integrity and left ventricular (LV) functional recovery in patients with acute myocardial infarction (MI) treated by primary coronary angioplasty (PTCA).

METHODS AND RESULTS

Thirty-one patients (27 males; age 39-76 years) with first, acute MI (<6 h after onset) were randomized to receive either abciximab+primary PTCA (n=17) or primary PTCA alone (n=14). Baseline characteristics of the two groups were similar. Myocardial reperfusion was studied shortly after PTCA by corrected TIMI frame count (cTFC) and intracoronary myocardial contrast echocardiography (MCE), after 48 h by intravenous MCE using intermittent, harmonic power Doppler, and after 1 month by intravenous MCE and 99 mTc-tetrofosmin SPECT. The patients treated with abciximab showed a shorter cTFC (23+/-4 vs 30+/-9 frames; P<0.05), a more preserved microvascular integrity shortly after PTCA (77% vs 55%; P<0.01), after 48 h (86% vs 50%; P<0.005) and at 1-month follow-up (86% vs 54% by MCE, P<0.001, and 68% vs 60% by SPECT, P<0.005) than patients treated with PTCA alone. Abciximab patients also showed a better recovery of LV function, as demonstrated by greater reduction in wall motion score index (1.4+/-0.3 vs 1.5+/-0.2; P<0.05) and increase in LV ejection fraction (53+/-7% vs 48+/-5%; P<0.001).

CONCLUSIONS

Abciximab improves microvascular perfusion and LV functional recovery in primary PTCA.

Acute-phase reactants in acute myocardial infarction: impact on 5-year prognosis

BACKGROUND

Acute-phase reactants have recently been shown to have a short-term and possibly long-term prognostic value in acute coronary syndromes. The aim of the present study was to retrospectively verify whether serum levels of inflammation markers can predict the occurrence of early and late cardiac events after myocardial infarction.

METHODS

We reevaluated 58 consecutive patients (43 men and 15 women, mean age 66 +/- 12 years) admitted to our Center during 1993 with a first myocardial infarction. Patients with non-cardiac causes of inflammation were excluded, as well as patients with a left ventricular ejection fraction <40%. From the first blood sample obtained at admission, we evaluated C-reactive protein (CRP) and alpha1-acid glycoprotein (alpha1-AGP) serum levels, the erythrocyte sedimentation rate (ESR), fibrinogen levels, and the white blood cell (WBC) count. We also evaluated the highest level of serum cardiac markers. Follow-up data were collected for 55 patients in June 1999.

RESULTS

Five in-hospital and 13 delayed cardiac deaths occurred. The mean follow-up of current survivors was 5.9 +/- 0.4 years. Patients in whom cardiac death occurred had significantly higher CRP (7.4 +/- 4.1 vs 3.0 +/- 2.4 mg/dl, p < 0.001) and alpha1-AGP levels (160 +/- 38 vs 113 +/- 24 mg/dl, p < 0.001), ESR (63 +/- 30 vs 37 +/- 25 mm/hour, p < 0.001), and WBC count (13,727 +/- 3,853 vs 10,936 +/- 3,358/mm3, p = 0.004). At multivariate analysis, higher alpha1-AGP (p < 0.001) and CRP serum levels (p = 0.02) were independent predictors of cardiac death. Patients in whom cardiac events occurred during follow-up showed higher CRP (5.7 +/- 3.7 vs 1.6 +/- 1.5 mg/dl, p < 0.001) and alpha1-AGP levels (140 +/- 36 vs 101 +/- 23 mg/dl, p < 0.001) and ESR (50 +/- 30 vs 34 +/- 26 mm/hour, p = 0.06). Higher alpha1-AGP (p < 0.001) and CRP serum levels (p = 0.03) were independent predictors of the occurrence of cardiac events.

CONCLUSIONS

The present study shows that CRP and alpha1-AGP have an independent prognostic value in patients presenting with a first, uncomplicated myocardial infarction. Assays of these markers may help to better stratify patients hospitalized for acute coronary syndromes.

Usefulness of carotid intima-media thickness measurement and peripheral B-mode ultrasound scan in the clinical screening of patients with coronary artery disease

Previous observational studies have shown a relationship between carotid intima-media thickness (IMT) and coronary artery disease (CAD). In this study the authors evaluated the accuracy of the common carotid IMT measurement in predicting the presence and severity of CAD and the additional information offered by the detection of carotid, iliac, and lower limb plaques. One hundred and fifty consecutive patients were subjected to coronary angiography and carotid, iliac, and lower limb ultrasound scan. The mean value of six IMT measurements of the far wall of the common carotid artery was calculated in each patient. The mean IMT was significantly correlated to the number of stenosed coronary vessels (r = 0.43, p<0.001), although the positive and negative predictive value of mean IMT in identifying patients with CAD was low (81% and 46%, respectively). The combined information offered by IMT measurements and peripheral (carotid, iliac, and lower limb) plaque detection was then used to obtain the best multivariate regression model able to predict CAD status. The multivariate model showed a highly significant multiple correlation coefficient (r = 0.60, p<0.0001) and a sharp improvement in the negative predictive value (92%) with respect to the univariable model. B-mode ultrasound scan including common carotid IMT measurement and peripheral plaque detection may be of clinical value in the screening of patients with CAD.

Assessment of coronary vasomotor function: old and new tools

Atherosclerosis has an impact on the vasomotor reaction of coronary segments to iodinated non-ionic contrast agents. Angiographically normal coronary segments show divergent vasomotor reactions to iodixanol or iopromide according to the presence of, and distance from, a coronary atherosclerotic lesion. The mechanism responsible for the above-mentioned vasomotor effect does not seem to involve flow-mediated vasodilation or endothelial nitric oxide synthesis. On the other hand, a cyclooxygenase product may be, at least in part, responsible for the vasodilating effect of non-ionic agents on epicardial coronary arteries. These findings have potential clinical implications that are herein discussed.

The impact of coronary artery disease on the coronary vasomotor response to nonionic contrast media

BACKGROUND

Coronary artery disease (CAD) alters the vasomotor response to a variety of pharmacological agents. We tested the hypothesis that CAD also has an impact on the coronary vasomotor response to radiologic contrast media.

METHODS AND RESULTS

We performed quantitative coronary angiography in 42 patients without angiographic evidence of CAD and 38 patients with CAD in the left coronary artery. Angiographically smooth coronary segments (n=235) were analyzed for changes on luminal diameters and coronary venous oxygen saturation in response to 3 media: the nonionic dimer iodixanol, the nonionic monomer iopromide, and the ionic agent ioxaglate. In subjects without CAD, we assessed the effects of intracoronary administration of the nitric oxide synthase inhibitor N(G)-monomethyl-L-arginine and of the cyclooxygenase inhibitor indomethacin on such changes. Iodixanol induced coronary vasodilation in subjects without CAD (8.8+/-8.6%, P<0.001). Patients with CAD exhibited no significant diameter changes in segments >/=20 mm apart from a stenosis (4.7+/-9.4%, P=NS) and significant constriction in segments <20 mm from a stenosis (-3.8+/-4.6%, P<0. 05). Similar results were obtained with iopromide, but no changes were found with ioxaglate. All contrast media induced transient (<35 seconds) increases in coronary venous oxygen saturation in all subjects. Indomethacin, but not N(G)-monomethyl-L-arginine, blunted the vasodilating effect of iodixanol and iopromide (by 80% and 76%, respectively; P<0.001).

CONCLUSIONS

Nonionic contrast media induce a vasodilatory response in normal vessels not by a mechanism involving increased flow or endothelial nitric oxide synthesis, but rather by depending on preserved vascular cyclooxygenase activity. CAD changes normal epicardial vasodilatory response into vasoconstriction.

Endothelin-1 release from atherosclerotic plaque after percutaneous transluminal coronary angioplasty in stable angina pectoris and single-vessel coronary artery disease

To assess the effects of percutaneous transluminal coronary angioplasty on endothelin-1 (ET-1) release, we assessed ET-1 concentrations at different sites of the coronary circulation in patients submitted to elective procedures. ET-1 levels immediately downstream from the plaque and ET-1 aortocoronary gradient increased significantly after the procedure, which was related to mechanical wall stress in patients only receiving balloons, but not in those undergoing stent percutaneous transluminal coronary angioplasty. No changes were found in the coronary sinus; these results suggest ET-1 release from the plaque rather than an ischemia/reperfusion-related production from the distal myocardium.

[Effects on vasomotor tone and hemostatic function of radiologic contrast media used during invasive cardiological procedures]

There are several types of radiologic contrast media which can be used in invasive cardiology: 1) ionic media with high osmolality (2000 mOsm/kg, about 6 times that of plasma), the prototype of which is diatrizoate; 2) ionic media with low osmolality (600-900 mOsm/kg), the prototype of which is ioxaglate; 3) non-ionic monomeric, low-osmolality media, such as iopromide, iopamidol and iohexol; and 4) non-ionic dimeric media, iso-osmolal compared to plasma (290-300 mOsm/kg), among which the most used is iodixanol. Non-ionic media--by far the most expensive--have a generally better tolerability profile for the patient, since they clearly induce a less gastro-intestinal, renal, hemodynamic, electrophysiological and pseudo-allergic side effects. They interfere much less with the physiology of vascular and circulating blood cells, and have lesser negative interference on the hemostatic function. Whether these lesser anti-hemostatic properties become a possible downside in situations at high thrombotic risk, such as in some interventional procedures, has been so far the object of isolated reports, usually with limited numbers of patients, and is presently being verified in adequate clinical trials. Radiologic contrast media also have disparate vasoactive properties on epicardial and myocardial resistance vessels. The knowledge and awareness of such effects is of potential importance for the performance of studies requiring the accurate quantitative evaluation of coronary diameters or of myocardial blood flow.

Coronary collateral circulation behaviour and myocardial viability in chronic total occlusion treated with coronary angioplasty

AIMS

We explored the role of microcirculation integrity following the chronic occlusion of an infarct-related artery to assess the behaviour of collateral circulation during and after reperfusion by coronary angioplasty

METHODS AND RESULTS

Eighteen patients with a proximally occluded left anterior descending artery and firm evidence of intercoronary collateral circulation were studied with selective coronary angiography and selective intracoronary myocardial contrast echocardiography, before coronary angioplasty, and at 5 and 15 min and 12 h later. Myocardial enhancement during myocardial contrast echocardiography was evaluated with a semiquantitative score (0-3), which was correlated to basal and 6 months' regional left ventricular wall motion results. 16/18 procedures were successfully performed; four patients with an inadequate acoustic window were excluded. Restenosis was evident at the 6 months' follow-up in two patients. Basal myocardial contrast echocardiography indicated that 81/192 segments from the left anterior descending coronary artery and 90/192 from the right coronary artery were perfused; no perfusion was observed in 21 segments either before or after coronary angioplasty. After coronary angioplasty, the angiographic intercoronary collateral circulation immediately disappeared, and myocardial contrast echocardiography revealed that there was a progressive reduction of segments perfused by the right coronary artery and an increase in segments perfused by the left anterior descending coronary artery. Regional left ventricular wall motion analysis demonstrated that there was abnormal motion in 51/192 segments. There was no improvement in segments with score 0 and abnormal motion after 6 months (100% sensitivity), but 16/17 segments with score 3 did show an improvement (98% specificity). The predictive value of intermediate scores (1-2) in detecting long-term improvement, was only 43%.

CONCLUSION

These data show that the adaptive mechanism observed in the behaviour of epicardial and microvascular circulation after reperfusion of a chronic occluded infarct-related artery can vary. In addition, this study clearly shows that microvascular integrity detected by myocardial contrast echocardiography can provide myocardial viability.

Altered autonomic cardiac control in hypertrophic cardiomyopathy. Role of outflow tract obstruction and myocardial hypertrophy

AIM

The goal of this study was to investigate the role of left ventricular outflow tract obstruction and myocardial hypertrophy on autonomic cardiac function in patients with hypertrophic cardiomyopathy.

METHODS AND RESULTS

The sympatho-vagal function was evaluated by spectral analysis of heart rate variability in 28 patients with hypertrophic obstructive cardiomyopathy, 22 patients with hypertrophic non-obstructive cardiomyopathy, 12 with systemic hypertension and left ventricular hypertrophy and 28 healthy subjects. Left ventricular out-flow tract pressure gradient in patients with hypertrophic cardiomyopathy was evaluated by echo-Doppler methods and the quantitative assessment of left ventricular hypertrophy was based on an echocardiographic index. At rest, patients with hypertrophic non-obstructive cardiomyopathy showed normal spectral patterns, while in patients with hypertrophic obstructive cardiomyopathy and in patients with systemic hypertension we observed, respectively, a significant reduction and increase in the low frequency component relative to the control (P < 0.05). During tilt, the physiological increases in the low frequency component and in the low to high frequency ratio were markedly blunted, or even reverted, only in patients with hypertrophic obstructive cardiomyopathy. In these patients, the heart rate increase during tilt was delayed in comparison to the other groups. Finally, in the hypertrophic obstructive cardiomyopathy group, the impairment of sympathetic activation (lack of increase in the low frequency component during tilt) was significantly correlated to the echocardiographic index of left ventricular hypertrophy (r = -0.800, P < 0.001) rather than to the left ventricular outflow tract pressure gradient (r = 0.295, P: ns).

CONCLUSION

Among patients with hypertrophic cardiomyopathy, only those with outflow tract obstruction show spectral signs of altered autonomic cardiac control. Within this group, the autonomic dysfunction appears to be correlated to myocardial hypertrophy rather than to left ventricular outflow tract obstruction.

Alteration of cardiac function in patients with temporal lobe epilepsy: different roles of EEG-ECG monitoring and spectral analysis of RR variability

PURPOSE

Because several reports have described the relation between epilepsy and cardiac arrhythmias and suggest that changes in autonomic neural control of the heart could be involved in the pathogenesis of sudden unexplained death in patients with epilepsy, the aim of this study was to evaluate cardiac function in patients with temporal lobe epilepsy.

METHODS

Sixty-five patients with epilepsy were evaluated by simultaneous ambulatory 24-h EEG-ECG monitoring, and in 30 of these, power spectral analysis of relative-risk (RR) variability also was carried out, both in the supine position and in a passive tilt position at 60 degrees. The power spectrum of RR variability, the two major spectral components detectable at low frequency (LF) and at high frequency (HF), respectively, and the LF/HF ratio were calculated.

RESULTS

By EEG-ECG monitoring, we recorded six partial seizures, and in four cases, discharges were associated with sinus tachycardia. However, interictally the occurrence of ventricular and supraventricular arrhythmias was not different from that in normal subjects. The spectral analysis of RR variability, on the other hand, demonstrated in patients with epilepsy a significant decrease in the total RR variability and in both of its components (LF and HF) in the supine position, and of the LF/HF ratio in orthostatic position.

CONCLUSIONS

These findings suggest that the spectral analysis of RR variability may detect disorders of autonomic cardiac control in patients with epilepsy, even in the absence of abnormal findings during ECG monitoring. This alteration, which is more severe in cases with right EEG focus, could play a role in the pathogenesis of cardiac arrhythmias.

[Incidence of peripheral vascular complications in subjects undergoing coronary angioplasty]

The peripheral vascular complications following cardiac catheterization for interventional procedures are increasing. The aim of our study is to evaluate the importance of the early removal of the arterial sheath in reducing vascular complications. We examined 451 consecutive patients, submitted to percutaneous transluminal coronary angioplasty (PTCA) by femoral approach. In 229 patients (Group A), we removed the arterial sheath 12-14 hours after PTCA; in 222 patients (Group B) the arterial sheath was removed as soon as possible at the end of PTCA. In 31 Group A and 5 Group B patients we performed a coronarographic study after 12-14 hours. In total, 16 patients (11 Group A, 5 Group B) presented vascular complications. None of the risk factors that we have considered was predictive for complications, except that iliacofemoral atherosclerotic disease. In patients undergoing complex procedures we have found a greater amount of vascular complications. The coronarographic control revealed some pathologic lesion (dissection, occlusive thrombus) only in patients with clear ischemic signs or symptoms, both in Group A and B. In our opinion, an early removal of the arterial sheath reduces the incidence of vascular complications and the period of in-hospital stay.

[Spectrum analysis of heart rate variability in obstructive hypertrophic myocardiopathy. Evidence of altered autonomic function]

Altered sympathetic activity may play an important role in the pathogenesis of hypertrophic obstructive cardiomyopathy (HOCM). Spectral analysis of heart rate variability was employed to assess the sympatho-vagal function and balance in 18 patients with HOCM (11 males, 7 females, mean age 42 years, range 19-59) and in 15 healthy control subjects (9 males, 6 females, mean age 44 years, range 18-65). Electrocardiographic recordings obtained both at rest and during 60 degrees passive tilt, were digitized and analyzed by fast Fourier transform in order to obtain the power spectrum of heart rate variability. The low-frequency band (LF: 0.05-0.17 Hz) and the high-frequency band (HF: 0.18-0.34) of power spectrum were considered as indexes of sympathetic and vagal activities respectively. A semiquantitative two-dimensional echocardiographic score (SES) was used to assess the entity of myocardial hypertrophy whereas the entity of the intraventricular gradient was determined by continuous wave Doppler. Low-frequency band at rest was slightly but significantly reduced in HOCM group with respect to controls (35.2 +/- 2.0 vs 45.0 +/- 2.5 nu, respectively; p < 0.01), whereas the HF band and the LF/HF ratio were not different in the 2 groups. During tilt, control subjects showed a significant reduction of the HF band (-35%, p < 0.001), an increase in the LF band (+36%, p < 0.001) and a sharp increase in the LF/HF ratio (+105%, p < 0.001). On the contrary the baroreflex increase in the LF band and LF/HF ratio during tilt was markedly blunted, or even reverted, in patients with HOCM (-9%, NS and +5%, NS, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of verapamil, gallopamil, diltiazem and nifedipine on sarcoplasmic reticulum function in rat heart

We investigated the effect of the calcium antagonists verapamil, gallopamil, diltiazem and nifedipine on cardiac sarcoplasmic reticulum function. In a cell-free homogenate from rat hearts, oxalate-supported Ca uptake was stimulated by verapamil, gallopamil and diltiazem at concentrations in the order of 10 nM to 100 nM, while higher concentrations were ineffective. Nifedipine was also ineffective. Peak stimulation of Ca uptake averaged 15-20% of control. Ca uptake is the difference between active Ca transport by Ca-ATPase and passive efflux through sarcoplasmic reticulum channels. In the presence of 300 microM ryanodine, which blocks sarcoplasmic reticulum channels, Ca uptake increased by 50%, but no further stimulation was produced by the addition of any calcium antagonist, at concentrations ranging from 1 nM to 100 microM. In a fraction enriched in sarcoplasmic reticulum, no drug affected the activity of Ca-ATPase at concentrations able to stimulate Ca uptake. We conclude that low concentrations of verapamil, gallopamil and diltiazem reduce Ca efflux through the Ca channels of the sarcoplasmic reticulum. Such an action might contribute to the clinical effect of these drugs.

[Effects of oxygen free radicals on the function of the cardiac sarcoplasmic reticulum]

Peroxidative stress, exerted by oxygen free radicals, seems to be an important mechanism of the ischemia-reperfusion myocardial damage. In the present study we evaluated the modifications of sarcoplasmic reticulum function subjected to peroxidation by ferric ions. A subcellular fraction enriched in sarcoplasmic reticulum was obtained from rabbit hearts by homogenization and differential centrifugations. Sarcoplasmic reticulum vesicles were peroxidated through incubation for 5 min at 37 degrees C in presence of ferric cloride (FeCl3) ranging in concentration between 0.3 and 0.9 mM. Peroxidation of sarcoplasmic reticulum vesicles determined a dose-dependent reduction of Ca-uptake (39.2 +/- 10.3, 36.5 +/- 9.9, 28.9 +/- 8.4 and 18.8 +/- 8.2 nmol/min/mg in presence of 0, 0.3, 0.6 e 0.9 mM FeCl3; NS, p less than 0.05 and less than 0.01, respectively) which was paralleled by an increase in the production of malondialdehyde, an index of lipid peroxidation (1.0 +/- 1.0, 7.0 +/- 3.2, 14.1 +/- 3.9 and 27.0 +/- 4.7 nmol/mg in presence of 0, 0.3, 0.6 e 0.9 mM FeCl3; p less than 0.05, less than 0.01 and less than 0.01, respectively). Depression of Ca-uptake was not accounted for by modifications of Ca-ATPase activity or membrane aspecific permeability to Ca++ ions, since these parameters were not affected by exposure to 0.3-0.9 mM FeCl3. On the contrary, the responsiveness of Ca-release channels to the specific inhibitor ryanodine was greatly altered, even at lower FeCl3 concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

[Coronary disease in patients operated on for valvulopathy]

In order to evaluate the influence of a significant coronary artery disease in patients with valvular heart disease or with prosthetic valves, we reviewed literature and our own experience. The incidence of coronary artery disease in valvulopathies has been diffusely studied and reported and, in a consecutive series of our hemodynamic studies, resulted 11%. The influence of a coronary artery disease on early and late results of a surgical procedure is different whether the coronary artery disease is operated or not. In particular, the combined surgery shows a higher early mortality, but a much better long-term prognosis. In addition, sometimes surgery introduces rare causes of coronary artery disease. Finally, it seems that coronary artery disease arises very rarely in patients undergone valvular surgery or, at least, patients rarely complain anginal symptoms in the post-surgical follow-up. In our experience on 529 patients only 6 complained typical angina and only 2 showed a coronary artery disease not present at the time of operation.

Evaluation of pulmonary vascular pressures in cardiac patients: the role of the chest roentgenogram

In 77 patients (34 with left heart valvulopathy, 17 with dilated cardiomyopathy, and 26 with chronic coronary artery disease) pulmonary vascular pressures were estimated from the chest film by means of a new scoring system. Standard chest x-ray films taken immediately before diagnostic right and left cardiac catheterization were analyzed independently by three readers without knowledge of the hemodynamic findings. The radiographic signs were subdivided into three groups as follows, and to each one a score derived from a retrospective statistical analysis was attributed: (A) signs of interstitial edema, (B) patterns of pulmonary blood flow distribution, and (C) alterations in the pulmonary arteries. The sum of the scores of groups A and B x-ray findings correlated well with pulmonary wedge pressure, and the sum of the scores of groups A, B, and C correlated more strongly with the mean pulmonary artery pressure. These results confirm that it is possible, in patients with chronic heart disease, to assess accurately the pulmonary artery and wedge pressures by means of the noninvasive and easily performed chest roentgenogram.

Cardiac alpha-crystallin. III. Involvement during heart ischemia

Rat hearts were perfused in the working heart or Langendorff mode and then subjected to total normothermic ischemia. The content of alpha-crystallin in the water soluble protein fraction obtained from these hearts diminished in a time-dependent manner during ischemia. The protein was recovered in the low g pellet of the homogenate. The redistribution was dramatic, selective for alpha-crystallin and irreversible. Large crystallin clumps formed also when exposing the soluble protein fraction of control hearts to slightly acidic pH (6.5-7.0). Electron microscopic analysis showed that aggregation of the globular homo-oligomeric units of crystallin occurred. The aggregates probably represented denatured protein and were similar in appearance to lenticular alpha H-crystallin. In purified form, however, cardiac crystallin particles did not cluster at pH 6.5. Aggregation only occurred in the presence of other protein components (including, probably, cytosolic actin) of the soluble fraction. A direct and selective interaction between actin and cardiac crystallin could be demonstrated using actin-Sepharose affinity chromatography procedures. The results suggest that large aggregates of cardiac crystallin form very early during ischemia, due to acidification of the cytosol. Cardiac crystallin is highly homologous to stress proteins and is localized on the Z-disks, where it plays probably a structural or protective role. Its rapid and complete denaturation could be involved in the genesis of the irreversible structural damages occurring during ischemia.

Purine release from isolated rat heart: a new approach to the study of energy metabolism

The rate of release of purines (adenosine, inosine, hypoxanthine, xanthine and uric acid) from isolated working rat hearts was measured and compared to tissue concentrations of high energy phosphate compounds. Hearts were subjected to different workloads, and perfusions were performed: with normal oxygen supply (group 1); with the addition of insulin to the standard perfusion buffer, which contained glucose as energy source (group 2); in hypoxic conditions (group 3). In each group purine release increased (P less than 0.01) at higher workload and was closely related to indices of mechanical performance such as cardiac output or minute work (r = 0.902 and 0.858 in group 1, r = 0.902 and 0.851 in group 2, r = 0.851 and 0.881 in group 3, P less than 0.001 in each case). Work had no effect on adenine nucleotides but produced a significant (P less than 0.01) reduction in phosphocreatine/creatine ratio. The comparison of different groups showed that at any level of heart performance purine release was higher (P less than 0.001) in group 3 vs. group 1, and lower (P less than 0.001) in group 2 vs. group 1. High energy phosphates were reduced in group 3 vs. group 1 but were unchanged in group 2 vs. group 1. We conclude that in the isolated heart purine release is directly related to the rate of energy consumption, and inversely related to the rate of energy production. Purine release provides a sensitive method to evaluate myocardial energy metabolism, which is more sensitive than measurement of high energy phosphates.

Adenine nucleotide depletion and contractile dysfunction in the "stunned" myocardium

STUDY OBJECTIVE

The aim of the study was to assess the contribution of adenine nucleotide depletion to postischaemic myocardial dysfunction ("stunned" myocardium).

DESIGN

Isolated perfused hearts release purine catabolites even in the absence of ischaemia, and undergo spontaneous reduction of adenine nucleotide pool. A comparison was therefore made between mechanical function, purine release and tissue adenine nucleotides in working rat hearts reperfused after short term ischaemia or subjected to prolonged perfusion (up to 180 min).

EXPERIMENTAL MATERIAL

49 Sprague-Dawley rats of 250-300 g body weight were used. The animals were anaesthetised and the hearts quickly excised and perfused with the working heart technique.

MEASUREMENTS AND MAIN RESULTS

Reperfusion after 10 min ischaemia provided a good model of "stunned" myocardium: aortic flow and minute work decreased by 15(SEM 2)% and 20(3)%, no enzyme leakage was observed, and the adenine nucleotide pool decreased by 3.5(0.4) mumols.g-1. During prolonged perfusion no change was observed in any haemodynamic variable until the adenine nucleotide pool was depleted by over 8.5 mumols.g-1. Adenylate energy charge and the phosphocreatine-creatine pool were unchanged in all cases.

CONCLUSIONS

Depletion of adenine nucleotides does not account for contractile dysfunction in our model of "stunned" myocardium.

Sarcoplasmic reticulum function in the "stunned" myocardium

Transient ischemia does not induce myocardial necrosis but may be associated with prolonged contractile dysfunction ("stunned" myocardium). It has been suggested that alteration of the excitation-contraction coupling system (sarcoplasmic reticulum) could be responsible for this phenomenon. We tested this hypothesis by characterizing sarcoplasmic reticulum (SR) function in an isolated rat heart model of "stunned" myocardium (hearts reperfused after 10 min of normothermic global ischemia). At the end of the ischemic period oxalate-supported Ca-uptake was depressed either in the whole homogenate or in isolated SR (to 47% and 22% of control values, respectively). During reperfusion Ca-uptake of the whole heart homogenate recovered almost completely whereas slight but significant depression persisted in isolated SR (48 +/- 2 vs 67 +/- 4 nmol/min x mg, P less than 0.01). In the presence of ruthenium red or ryanodine, two inhibitors of SR Ca-release channels, Ca-uptake was stimulated. Both in the whole heart homogenate and in isolated SR, such stimulation was remarkably smaller after reperfusion than in control conditions (P less than 0.001) suggesting reduced conductivity state of the SR Ca-release channels. Ca-stimulated, magnesium-dependent ATPase activity was remarkably reduced during ischemia and postischemic reperfusion induced only incomplete recovery (93 +/- 18 vs 169 +/- 14 nmol ATP/min x mg protein, P less than 0.05). We conclude that complex modifications of SR function occur in the "stunned" myocardium and could contribute to the contractile impairment found in this condition.

The adenosine hypothesis revisited: relationship between purine release and coronary flow in isolated rat heart

We evaluated the adenosine hypothesis through a new approach, based on the study of the relationship between coronary flow or resistance and purine release, which is an accurate index of myocardial adenosine release. Isolated rat hearts were perfused at different work loads, in hypoxic conditions and after a short period of global ischaemia. When the results of all experiments were considered together, purine release was significantly but weakly related to coronary flow and coronary resistance (r = 0.416 v coronary flow, r = 0.378 v the reciprocal of coronary resistance, p less than 0.01). Closer relationships were obtained within the three subgroups: the correlation coefficients increased to 0.819 and 0.835 (p less than 0.001) in the hearts perfused at different work loads with normal oxygen supply, to 0.701 and 0.757 (p less than 0.02 and p less than 0.01) in the hypoxic hearts, and to 0.897 and 0.978 (p less than 0.02 and p less than 0.01) in the hearts recovering from ischaemia. The relationships between purine release and coronary flow or resistance were significantly different in the three subgroups (p less than 0.001): at any value of purine release coronary resistance was highest during hypoxia and lowest after ischaemia, while the opposite was true for coronary flow. We suggest that the adenosine hypothesis is converted into a "weaker" statement: adenosine is involved in the adjustment between heart performance and coronary resistance but other factors contribute to the regulation of coronary flow, and/or affect the response to adenosine.

Protection of isolated rat heart from oxidative stress by exogenous creatine phosphate

The influence of exogenous creatine phosphate (CP) on peroxidative heart injury was investigated in two experimental models: isolated working rat hearts and myocardial membrane preparations. In the first model the addition of 190 microM hydrogen peroxide to the perfusion buffer caused a marked decrease of aortic flow, minute work and peak aortic pressure, and leakage of intracellular enzymes. In the presence of 10 mM CP the hemodynamic damage produced by the same concentration of hydrogen peroxide was significantly lower and enzyme release was also remarkably reduced. The protection was concentration-dependent and the whole structure of the molecule was required since creatine was found to be ineffective. In the absence of hydrogen peroxide, CP and creatine did not affect heart performance. In microsomal membrane preparations CP decreased the formation of thiobarbituric acid-reactive material (malonaldehyde) induced by hydrogen peroxide in the presence of ferrous ions. This protection was concentration-dependent and occurred at physiological concentrations of CP. Also in this experimental model creatine had no effect and creatine plus inorganic phosphate was much less active than CP. The influence of CP on oxidative heart stress could account for the beneficial effect of this substance in different models of ischemic injury.