Silzone coating and paravalvular leak: an independent, randomized study.

BACKGROUND AND AIM OF THE STUDY: The study aim was to address independently, in a randomized patient cohort, the impact of Silzone coating on the prevalence and impact of paravalvular leak in patients undergoing mechanical valve replacement. METHODS: Randomized implantation of the uncoated St. Jude Medical Masters, and the Silzone-coated prosthesis was performed in 95 patients, excluding those with suspected or diagnosed infective endocarditis. The company did not support the study; this cohort is not contained in the AVERT trial. Following recall of the Silzone-coated valves, all patients in this cohort were invited to undergo control transthoracic echocardiography and plasma LDH determination. RESULTS: Silzone-coated valves were implanted in 46 patients (57 valves; 34 aortic, 20 mitral, three tricuspid), and uncoated valves in 49 patients (55 valves; 38 aortic, 16 mitral, one tricuspid). One patient with an uncoated mitral valve died from left ventricular dissection. In total, 73 patients returned for specifically planned echocardiography (mean interval 478+/-78 days). Sixteen patients underwent echocardiography on another occasion (mean interval 113+/-202 days). Six hospital survivors did not undergo any postoperative echocardiography. In total, 51 Silzone-coated valves (31 aortic, 18 mitral, two tricuspid), and 53 uncoated valves (37 aortic, 15 mitral, one tricuspid) were evaluated. No patients were reoperated for intrinsic or extrinsic valve dysfunction. No major paravalvular leaks were seen. Five of 51 Silzone-coated valves showed minimal (grade <1+; four aortic, one mitral) paravalvular leak when specifically sought; two showed minimal (grade <1+; one aortic, one mitral), and one slight (grade 1+; one mitral) paravalvular leak in the uncoated group (p = 0.55). The LDH level was 654+/-163 U/I in the Silzone group, and 598+/-124 U/l in the control group (p = 0.10). CONCLUSION: No differences were detected in the incidence of paravalvular leak between Silzone-coated and uncoated mechanical St. Jude Medical valves. The incidence of major paravalvular leaks appears to be lower in the present cohort than was reported in the AVERT trial.

The value of dipyridamole thallium scintigraphy and dobutamine stress echocardiography as predictors of cardiac complications following reconstruction of the abdominal aorta.

BACKGROUND: The aim of this study was to evaluate the ability of dipyridamole thallium scintigraphy and dobutamine stress echocardiography to predict cardiac complications following elective reconstruction of the abdominal aorta in patients with a stable preoperative cardiac condition and to compare this with information obtained from the medical history, ECG and resting echocardiography alone. METHODS: This evaluation was performed from January 1993 until December 1995 as part of a prospective, randomised study in 200 patients, with a mean age of 65 (5% women). Dipyridamole thallium scintigraphy was performed on 195 patients and dobutamine stress echocardiography was added to the protocol in the last 83 patients. Cardiac complications were defined before the start of the study. RESULTS: In the postoperative period 62 cardiac complications occurred (31%). In patients clinically suspected of having coronary artery disease the incidence of complications was 40% (51/126), compared to 15% (11/74) when no coronary pathology was suspected (p<0.001). When reversible defects were present on dipyridamole thallium scintigraphy the incidence of complications was 36% (20/55), compared to 29% (41/140) when no reversible defects had been found (NS). Dobutamine stress echocardiography was impossible or contraindicated in 21 patients. In the remaining patients the incidence of complications was 71% (5/7) when new regional wall motion abnormalities were found, compared to 16% (9/55) when such abnormalities had not been detected (p<0.005). CONCLUSIONS: These data suggest that cardiac complications following reconstruction of the abdominal aorta in patients with a stable cardiac condition are best predicted by dobutamine stress echocardiography. Dipyridamole thallium scintigraphy, however, does not seem to be useful in this respect.

Postoperative hemodynamics of two bileaflet heart valves in the aortic position.

BACKGROUND AND AIMS OF THE STUDY: In vivo hemodynamic assessment of bileaflet aortic valve prostheses using standardized echocardiography is still uncommon; hence, adequate comparison of valve types can rarely be made. We compared the postoperative hemodynamics of St. Jude Standard valves (SJS) with those of Sorin Bicarbon valves (BC) implanted in the aortic position, using pulsed, continuous and color Doppler echocardiography. METHODS: The examination was performed four months after aortic valve prosthesis implantation in 76 patients (39 SJS valves, 37 BC valves). Valve sizes varied from 19 mm to 25 mm. Maximal and mean instantaneous pressure gradients were measured by Doppler echocardiography. Effective valve orifice area (EOA) was calculated and prosthetic valve regurgitation was assessed by color Doppler flow imaging. RESULTS: At valve sizes of 21 mm, 23 mm and 25 mm, SJS valves had a significantly lower EOAs than BC valves (p < 0.05). However, for a given nominal size, BC valves are larger, i.e. they have a larger anatomic (AOA) and geometric orifice area (GOA) than SJS valves. Consequently, BC valves were implanted in patients with a larger left ventricular outflow tract (p < 0.05). When EOA is related to the corresponding AOA, BC valves still show a larger EOA than SJS valves (p < 0.05). Prosthetic valve regurgitation is low in both valve types. CONCLUSIONS: (a) Nominal valve size is not always a good basis for comparison of hemodynamic profiles between valve types. (b) Using the relationship between EOA and AOA, the hemodynamic profile of BC valves in the aortic position is shown to be superior to that of SJS valves.

Can dobutamine echocardiography distinguish necrotic from ischemic myocardium, early after myocardial infarction?

UNLABELLED: The aim of this study was to evaluate the usefulness of dobutamine echocardiography (DE) in distinguishing necrotic from ischemic myocardium in infarct zones. We performed DE in 39 patients, 3 to 5 days after admission for a first, acute myocardial infarction, treated with thrombolysis. DE was considered positive if wall motion in the infarct zone worsened progressively during increasing dose of dobutamine or if wall motion in the infarct zone initially improved at low dose of dobutamine and deteriorated at higher dose. The results of DE were correlated to the evolution of wall motion in the infarct zone after 3 months and to the need for supplementary balloon dilatation. In 15 of the 39 patients, there was evidence of residual ischemia in the infarct zone. Twenty of the 39 patients had a positive dobutamine echocardiogram. Eleven of these 20 patients had evidence of residual ischemia in the infarct zone. They showed generalized changes of wall motion in the total infarct territory during DE. The other 9 patients demonstrated only localized changes of wall motion in isolated segments of the infarct zone during DE. None of these patients had evidence of residual ischemia. IN CONCLUSION: DE seems worthwhile in the detection of residual ischemia in the region of infarction. To reduce the number of false positive DE early after myocardial infarction, only extensive changes of wall motion in the total infarct territory should be accepted as indicative of residual ischemia in the infarct zone.

Echocardiographic detection of acute myocardial ischemia during percutaneous transluminal coronary angioplasty.

The usefulness of echocardiography and Doppler for the detection of acute myocardial ischemia was evaluated during right coronary artery occlusion in 20 patients. The echocardiographic findings were compared with the occurrence of chest pain, and to electrocardiographic and hemodynamic changes obtained during percutaneous transluminal coronary angioplasty. Our results confirm that, even in the case of small segmental myocardial ischemia, two-dimensional echocardiography is superior to all other measured parameters. In contrast, Doppler examination of transmitral flow is not sensitive enough for the detection of such small segmental myocardial ischemia induced by right coronary artery occlusion.

Frequency of angina pectoris and coronary artery disease in severe isolated valvular aortic stenosis.

A consecutive series of 192 patients (121 men and 71 women, mean age 59 years, range 28 to 82) with isolated, severe valvular aortic stenosis was with isolated, severe valvular aortic stenosis was analyzed retrospectively to determine the relation of angina pectoris and coronary risk factors to angiographically significant coronary artery disease (CAD). Significant CAD (diameter reduction greater than or equal to 50%) was found in 47 patients (24%). Angina was present in 83% of them, but it was also found in 61% of the non-CAD patients. This symptom had as a result a low positive predictive value (31%). Of the patients without angina (n = 65) 12% had significant CAD. The negative predictive value of angina alone was thus 88%. By using multivariate logistic regression, a risk score could be calculated based on angina, age and sex, which increased the negative predictive value to 95%. It was concluded that coronary arteriography can only be omitted in severe aortic valvular stenosis, when patients have no angina and when they are less than 40 years of age for men and less than 50 years for women. For all other cases, coronary arteriography should be recommended.