Michael B. Harding

Ergonovine maleate testing during cardiac catheterization: a 10-year perspective in 3,447 patients without significant coronary artery disease or Prinzmetal's variant angina.

The utility of ergonovine testing for coronary artery spasm was assessed in 3,447 patients with angiographically insignificant (less than 50% diameter stenosis) or no coronary artery disease. No patients clinically had Prinzmetals variant angina. Overall, 4% had a positive ergonovine test result, defined by spasm causing greater than or equal to 75% focal stenosis. Complications related to ergonovine use occurred in 11 patients (0.03%). In a training sample of 1,136 patients (studied between 1980 and 1984), two independent predictors of spasm were found by using multivariate analysis: the amount of visible coronary artery disease on the coronary angiogram (p less than 0.0001) and a smoking history (p = 0.001). A model to predict spasm based on these variables was validated in a test group of 2,311 patients who received ergonovine from 1985 to 1989. This model allowed the identification of a subset of 400 patients in the validation sample who had a 10% positive test rate compared with a 2% positive test rate in the remaining patients. These results should permit clinicians who use provocative testing in the catheterization laboratory to reserve testing for the subset of this group of patients most likely to have abnormal findings.

Left ventricular filling and ventricular diastolic performance after percutaneous balloon mitral valvotomy.

The time course of left ventricular (LV) filling and LV diastolic performance were examined in 27 consecutive patients in sinus rhythm before and acutely after balloon mitral valvotomy (BMV). The mitral valve area acutely increased from 1.1 +/- 0.3 to 2.1 +/- 0.8 cm2. Simultaneous pressure-volume data were obtained using digital subtraction left ventriculography and LV micromanometer pressure before and 10 minutes after BMV. The time constant of LV isovolumic relaxation was unchanged after BMV (50 +/- 10 ms before BMV vs 47 +/- 13 ms after BMV). In addition, values before and after BMV for LV end-diastolic volume (123 +/- 29 vs 125 +/- 36 ml), end-diastolic pressure (11 +/- 4 vs 12 +/- 4 mm Hg) and diastolic filling time (337 +/- 126 vs 338 +/- 152 ms) were not altered by the procedure. After BMV the peak diastolic filling rate (403 +/- 143 vs 469 +/- 302 ml/s) was maintained despite a 36% reduction in left atrial filling pressure. There was a trend toward earlier occurrence of the peak filling rate (196 +/- 127 vs 146 +/- 148 ms, p = 0.08). The percentage of diastolic filling in the first third of diastole, however, was similar (42 +/- 9 vs 48 +/- 16%) before and after the procedure. Thus, the time course of LV filling is not significantly altered acutely after BMV, but is maintained at reduced left atrial filling pressure. Neither LV relaxation or LV chamber compliance are altered acutely after BMV.(ABSTRACT TRUNCATED AT 250 WORDS)

Fibrin modification by ionic and nonionic contrast media during cardiac catheterization

T he rare but serious complication of thromboembolism during cardiac catheterization is believed to be a result of an imbalance between the prothrombotic nature of the invasive procedure and the antithrombotic effects of adequate catheter flushing and of the contrast agents themselves. Although thrombotic complications may occur as a result of an identifiable problem in procedural technique, thrombosis sometimes occurs without explanation.’ Both ionic and nonionic contrast media are known to have an inhibitory effect on platelet aggregation and blood clotting in vitro2-9; however, nonionic contrast has been shown to have a less inhibitory effect,3-5*7-9 and therefore could theoretically result in a greater tendency for thrombosis.tO Hwang et al” showed that use of the nonionic agents iohexol and iopamidol was associated with coronary thromboembolism during cardiac catheterization in dogs, whereas the ionic agents ioxaglate and diatrizoate were not associated with such clotting complications. It has also been observed that clots embolized into coronary arteries during catheterization are particularly difficult to dissolve with thrombolytic therapy.t2 Both the ionic contrast agent diatrizoate and the nonionic agent iopamidol have been shown in vitro to cause changes in fibrin assembly and structure, resulting in thin fibrin fibrils,6 which render the fibrin resistant to fibrinolysis. Fibrin with low mass/length ratio in certain disease states has been shown to be resistant to fibrinolysis.13 Demonstration of fibrin changes in vivo during cardiac catheterization would provide further evidence that the in vitro changes have clinical relevance, including providing a possible explanation for why contrast-induced thrombus is resistant to fibrinolysis. This study evaluates the effects of ionic and nonionic contrast media on fibrin assembly and structure by analyzing samples obtained at critical times and anatomic locations during cardiac catheterization. Twenty-three patients undergoing cardiac catheterization between March 14,1990, and July 12,1990, were prospectively studied. Exclusion criteria were as follows: history of bleeding disorder, hypercoagulable state, treatment with warfarin or heparin, hematocrit <30%, platelet count <150,000, abnormally elevated protime or partial thromboplastin time, uncontrolled angina at rest, or myocardial infarction within 3 months. The indication for cardiac catheterization was suspicion of coronary artery disease due to chest pain or a positive func-

Comparison of cardiovascular and renal toxicity after cardiac catheterization using a nonionic versus ionic radiographic contrast agent

Abstract Both ionic and nonionic contrast agents used in angiography are relatively well tolerated but have a number of undesirable effects, particularly on the cardiovascular system and the kidney. 1–7 Whereas low osmolar agents may reduce acute events, contrast nephropathy remains a common cause of in-hospital renal injury, and the potential advantage of one contrast agent over another is less well defined. 2,3 The best method of evaluating the relative toxicity of iopamidol and diatrizoate is by a randomized controlled clinical trial. In principle, there are 2 major designs for a randomized trial: (1) a cohort trial that compares results between different patients, and (2) a crossover trial that compares results within the same patient. The crossover design provides the greatest assurance that between-patient differences will not affect the results, and this design is generally well suited for investigations of pharmaceuticals. As part of a randomized trial using a cohort design, 1,2 we prospectively designed a crossover protocol so that any patient randomized in the trial would receive the alternative contrast agent if a second coronary angiogram proved to be clinically indicated within the study period. In all, 67 of the 443 randomized patients had a second procedure, 41 of whom received the alternative agent. This report summarizes the results of 41 randomized patients in this prospective controlled crossover investigation.

Determinants of one-year outcome from balloon aortic valvuloplasty☆

Balloon aortic valvuloplasty (BAV) has been a therapeutic alternative treatment for severe symptomatic aortic stenosis. Previous studies have been unable to predict 1-year outcome because of limited acute and follow-up clinical, invasive and echocardiographic data. The purpose of this study was to predict long-term outcome based on comprehensive data obtained at the time of valvuloplasty and at 3 and 6 months after the procedure. Of 170 consecutive patients undergoing BAV, 108 (mean age 78 years) were at least 1 year from their procedure. Prospective clinical, micromanometer hemodynamic, digital ventriculographic and echocardiographic/Doppler data were collected at baseline and immediately after the procedure. Echocardiographic data were also obtained at 3 and 6 months. With use of Cox model analysis, major events (defined as cardiac death [n = 30], aortic valve replacement [n = 21] or repeat BAV [n = 13]) were predicted by advanced age, baseline heart failure class, and baseline echocardiographic-determined diastolic left ventricular diameter. Only baseline left ventricular ejection fraction proved to be a significant predictor of cardiac death (p = 0.002) in a multivariate model. Absolute values after BAV (stroke work, first derivative of left ventricular pressure, valve area, end-systolic volume, Fick cardiac output, transvalvular gradient) and acute changes measured by catheterization or echocardiography did not provide additional predictive information over that of post procedure ejection fraction. Similarly, echocardiographic valve area and transvalvular gradient at 3 months added no further prognostic data. With an ejection fraction greater than or equal to 45% (n = 63), cardiac survival at 1 year was 80%, irrespective of age, sex, congestive heart failure class or severity of coronary artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)