Walter Bleifeld

A Randomized Study of Coronary Angioplasty Compared with Bypass Surgery in Patients with Symptomatic Multivessel Coronary Disease

BACKGROUND The standard treatment for patients with symptomatic multivessel coronary artery disease is coronary-artery bypass grafting (CABG). Percutaneous transluminal coronary angioplasty (PTCA) is widely used as an alternative approach to revascularization, but a systematic comparison of the two procedures is needed. We compared the outcomes in patients one year after complete revascularization with CABG or PTCA. METHODS A total of 8981 patients with multivessel coronary disease were screened at eight clinical sites, and 359 patients were randomly assigned to undergo CABG (177 patients) or PTCA (182 patients). Enrollment required that complete revascularization of at least two major vessels supplying different myocardial regions be deemed clinically necessary and technically feasible. RESULTS Among the patients in the CABG group, an average of 2.2 +/- 0.6 vessels were grafted, and among those in the PTCA group, 1.9 +/- 0.5 vessels were dilated. After CABG, hospitalization was longer (median, 19, as compared with 5 days for PTCA), and Q-wave myocardial infarction in relation to the procedure was more frequent (8.1 percent, as compared with 2.3 percent after PTCA; P = 0.022), whereas in-hospital mortality did not differ significantly between the two groups (2.5 percent in the CABG group and 1.1 percent in the PTCA group). At discharge 93 percent of the patients in the CABG group were free of angina, as compared with 82 percent of those in the PTCA group (P = 0.005). During the first year of follow-up, further interventions were necessary in 44 percent of the patients in the PTCA group (repeated PTCA in 23 percent, CABG in 18 percent, and both in 3 percent) but in only 6 percent of the patients in the CABG group (repeated CABG in 1 percent and PTCA in 5 percent; P < 0.001). Seventy-four percent of the patients in the CABG group and 71 percent of those in the PTCA group were free of angina one year after treatment. Exercise capacity improved similarly in both groups. However, 22 percent of the CABG group, as compared with only 12 percent of the PTCA group, did not require antianginal medication (P = 0.041). CONCLUSIONS In selected patients with multivessel coronary disease, PTCA and CABG as initial treatments resulted in equivalent improvement in angina after one year. However, in order to achieve similar clinical outcomes, the patients treated with PTCA were more likely to require further interventions and antianginal drugs, whereas the patients treated with CABG were more likely to sustain an acute myocardial infarction at the time of the procedure.

Transesophageal two-dimensional echocardiography for the detection of left atrial appendage thrombus

Thrombi located in the left atrial appendage are frequently not detected with conventional two-dimensional echocardiography. The transesophageal echocardiographic approach readily visualizes left atrial morphology and may be used as an alternative. In 6 of 21 patients with mitral valve stenosis, a left atrial appendage thrombus was diagnosed by transesophageal two-dimensional echocardiography when transthoracic echocardiography had failed. The transesophageal echocardiographic findings were confirmed at surgery for mitral valve replacement in all cases.

Left ventricular relaxation and filling pattern in different forms of left ventricular hypertrophy: An echocardiographic study☆

Abstract To study left ventricular relaxation and filling in different forms of left ventricular hypertrophy, echocardiograms of the left ventricle in 24 patients with hypertrophic obstructive cardiomyopathy and in 24 patients with chronic left ventricular pressure overload (due to aortic stenosis in 6 and to severe arterial hypertension in 18) were analyzed by computer and compared with those of 28 normal subjects. The relaxation time index (minimal left ventricular dimension to mitral valve opening) was 13 ± 15 ms in normal subjects. This index was prolonged in patients with cardiomyopathy (93 ± 37 ms) and overload (66 ± 31 ms). During the interval from minimal left ventricular dimension to mitral valve opening both groups with left ventricular hypertrophy showed a marked increase in left ventricular dimension of 4.0 ± 2.2 mm and 3.0 ±1.8 mm, respectively, which was significantly greater (p The rapid filling phase and the increase in dimension during this period were significantly reduced in hypertrophic obstructive cardiomyopathy and chronic pressure overload. In contrast to findings in the patients with cardiomyopathy, in those with pressure overload the reduced increase in left ventricular dimension during the rapid diastolic filling period was compensated for by a greater dimensional increase due to atrial contraction, resulting in a normal end-diastolic dimension. These data indicate that significant prolongation of isovolumic relaxation is seen in different forms of left ventricular hypertrophy and is often associated with an abnormal diastolic filling pattern.

Diagnosis of thoracic aortic dissection. Magnetic resonance imaging versus transesophageal echocardiography.

BackgroundAortic dissection requires prompt and reliable diagnosis to reduce the high mortality. The purpose of this study was to assess the reliability of both ECG-triggered magnetic resonance imaging (MRI) and transesophageal two-dimensional echocardiography combined with color-coded Doppler flow imaging (TEE) for the diagnosis of thoracic aortic dissection and associated epiphenomena. Methods and ResultsFifty-three consecutive patients with clinically suspected aortic dissection were subjected to a dual noninvasive imaging protocol in random order; imaging results were compared and validated against the independent morphological “gold standard” of intraoperative findings (n=27), necropsy (n=7), and/or contrast angiography (n=53). No serious side effects were encountered with either imaging method. In contrast to a precursory screening transthoracic echogram, the sensitivities of both MRI and TEE were 100% for detecting a dissection of the thoracic aorta irrespective of its location. The specificity of TEE, however, was lower than the specificity of MRI for a dissection (TEE, 68.2% versus MRI, 100%; p<0.005), which resulted mainly from false-positive TEE findings confined to the ascending segment of the aorta (TEE, 78.8% versus MRI, 100%; p<0.01). In addition, MRI proved to be more sensitive than TEE in detecting the formation of thrombus in the false lumen of both the aortic arch (p<0.01) and the descending segment of the aorta (p<0.05). There were no discrepancies between the two imaging techniques in detecting the site of entry to a dissection, aortic regurgitation, or pericardial effusion. ConclusionsBoth MRI and TEE are atraumatic, safe, and highly sensitive methods to identify and classify acute and subacute dissections of the entire thoracic aorta. TEE, however, is associated with lower specificity for lesions in the ascending aorta. These results may still favor TEE as a semi-invasive diagnostic procedure after a precursory screening transthoracic echogram in suspected aortic dissection, but they establish Mil as an excellent method to avoid false-positive findings. Anatomic mapping by MRI may emerge as the most comprehensive approach and morphological standard to guide surgical interventions.

Biochemical evidence of platelet activation in patients with persistent unstable angina

Thromboxane released from activated platelets and prostacyclin of the vessel wall may act as potent antagonistic modulators of platelet aggregability and coronary vascular tone. Therefore, urinary excretion of their major metabolites, 2,3-dinor-thromboxane B2 and 2,3-dinor-6-ketoprostaglandin F1 alpha, was studied in 16 patients presenting with prolonged angina at rest. The 10 patients whose condition did not improve under vigorous antianginal treatment within 48 hours exhibited higher thromboxane metabolite excretion than did the 6 patients who responded to therapy (2,208 +/- 1,542 versus 609 +/- 312 ng/g creatinine; p less than 0.001). Elevated values were also found in four of eight patients with sustained postinfarction angina. Enhanced thromboxane metabolite excretion was frequently associated with angiographic evidence of thrombus formation. When nine patients were restudied in a stable phase after 11 +/- 5 months, thromboxane metabolite excretion was consistently normal or high normal. Excretion of prostacyclin metabolites was not depressed in any patient but correlated weakly with thromboxane (r = 0.41). Thus, enhanced thromboxane production as an index of platelet activation may identify patients with active thrombus formation who could benefit most from platelet inhibitory treatment.

Effect of verapamil on left ventricular isovolumic relaxation time and regional left ventricular filling in hypertrophic cardiomyopathy

Hypertrophic obstructive and nonobstructive cardiomyopathy are often associated with an abnormal prolonged left ventricular isovolumic relaxation time and a disturbed left ventricular filling pattern [1–5]. Recent experimental studies revealed that calcium antagonists may improve impaired left ventricular relaxation caused by ischemia or hypoxia [6, 7]. Based on these experimental results, it was the purpose of the present study to examine whether the impaired left ventricular relaxation in patients with obstructive and nonobstructive hypertrophic cardiomyopathy can be improved by intravenous application of verapamil.

Noninvasive estimation of regurgitant flow rate and volume in patients with mitral regurgitation by doppler color mapping of accelerating flow field

OBJECTIVES This study was designed to examine the accuracy of proximal accelerating flow calculations in estimating regurgitant flow rate or volume in patients with different types of mitral valve disease. BACKGROUND Flow acceleration proximal to a regurgitant orifice, observed with Doppler color flow mapping, is constituted by isovelocity surfaces centered at the orifice. By conservation of mass, the flow rate through each isovelocity surface equals the flow rate through the regurgitant orifice. METHODS Forty-six adults with mitral regurgitation of angiographic grades I to IV were studied. The proximal accelerating flow rate (Q) was calculated by: Q = 2 pi r2.Vn, where pi r2 is the area of the hemisphere and Vn is the Nyquist velocity. Radius of the hemisphere (r) was measured from two-dimensional or M-mode Doppler color recording. From the M-mode color study, integration of accelerating flow rate throughout systole yielded stroke accelerating flow volume and mean flow rate. Mitral regurgitant flow rate and stroke regurgitant volume were measured by using a combination of pulsed wave Doppler and two-dimensional echocardiographic measurements of aortic forward flow and mitral inflow. RESULTS The proximal accelerating flow region was observed in 42 of 46 patients. Maximal accelerating flow measured from either two-dimensional (372 +/- 389 ml/s) or M-mode (406 +/- 421 ml/s) Doppler color study tended to overestimate the mean regurgitant flow rate (306 +/- 253 ml/s, p < 0.05). Mean Doppler accelerating flow rate correlated well with mean regurgitant flow rate (r = 0.95, p < 0.001), although there was a tendency toward slight overestimation of mean regurgitant flow by mean accelerating flow in severe mitral regurgitation. However, there was no significant difference between the mean accelerating flow rate (318 +/- 304 ml/s) and the mean regurgitant flow rate (306 +/- 253 ml/s, p = NS) for all patients. A similar relation was found between accelerating flow stroke volume (78.27 +/- 62.72 ml) and regurgitant flow stroke volume (76.06 +/- 59.76 ml) (r = 0.95, p < 0.001). The etiology of mitral regurgitation did not appear to affect the relation between accelerating flow and regurgitant flow. CONCLUSIONS Proximal accelerating flow rate calculated by the hemispheric model of the isovelocity surface was applicable and accurate in most patients with mitral regurgitation of a variety of causes. There was slight overestimation of regurgitant flow rate by accelerating flow rate when the regurgitant lesion was more severe.

Effect of encainide and flecainide on chronic ectopic atrial tachycardia

In the treatment of chronic ectopic atrial tachycardia, standard antiarrhythmic therapy has been shown to be ineffective in the majority of patients. The intravenous and oral effects of two class IC antiarrhythmic drugs, encainide and flecainide, in five patients with chronic ectopic atrial tachycardia were studied using exercise testing, 24 hour long-term electrocardiography and programmed electrical stimulation. All patients had been treated unsuccessfully with at least four antiarrhythmic drugs. In two patients tachycardia was persistent, and in three patients tachycardia occurred intermittently for more than 12 hours/day. Intravenous encainide and flecainide at doses ranging from 0.3 to 2.0 mg/kg and from 0.5 to 1.5 mg/kg body weight, respectively, terminated atrial ectopic tachycardia in all patients. Oral encainide, 150 to 225 mg/day, completely suppressed ectopic atrial activity in four patients during a mean follow-up period of 8 +/- 3 months. In the remaining patient encainide markedly reduced the number of episodes of tachycardia. In three patients encainide had to be withdrawn because of intolerable side effects. These patients were well controlled with oral flecainide, 200 to 300 mg/day, without side effects. On the basis of these results, the efficacy of encainide and flecainide in the treatment of chronic ectopic atrial tachycardia appears to be not drug-specific but rather a general class IC property.

Left ventricular hemodynamics and function in acute myocardial infarction: Studies during the acute phase, convalescence and late recovery

The left ventricular hemodynamics of 70 patients with acute myocardial infarction were determined from measurements of pulmonary arterial end-diastolic pressure, cardiac index, mean arterial pressure and heart rate during the acute phase(first study, 5 hours after admission), 4 to 6 weeks later (second study, during convalescence) and in 35 percent of all subjects 6 to 12 months after the acute infarction (third study). Serial analysis of serum creatine kinase was carried out during the acute phase. The peak CK value normalized for body surface area was used as a rough index of the extent of the acute myocardial necrosis. The condition of all survivors of the acute stage improved. Patients with only slightly reduced left ventricular performance during the acute stage recovered to nearly normal during convalescence. The condition of patients with greatly reduced left ventricular function also improved but remained impaired during convalescence. In all patients the main changes in left ventricular hemodynamics occurred within the first 4 to 6 weeks; there was almost no further alteration during the following 9 months.

Use of dual intracoronary scintigraphy with thallium-201 and technetium-99m pyrophosphate to predict improvement in left ventricular wall motion immediately after intracoronary thrombolysis in acute myocardial infarction

Thirty-one patients with acute myocardial infarction underwent intracoronary thrombolysis. Intracoronary thallium scintigrams were obtained before and 30 to 60 minutes after thrombolysis and thallium reinjection in all patients; intracoronary technetium-99m pyrophosphate scintigraphy was performed simultaneously after thrombolysis in 16 of the 31 patients. The scintigraphic results were compared with the changes in regional ejection fraction in the area of infarction. Two patients with inferior myocardial infarction had a normal left ventricular cineangiogram with no initial significant left ventricular thallium defect. In eight patients, regional ejection fraction normalized (from 18 to 63%, p No changes in thallium defect size or regional ejection fraction were observed in seven patients in whom thrombolysis failed. Intracoronary injection of technetium-99m pyrophosphate after thrombolysis revealed a localized accumulation in the area of the thallium defect with or without significant thallium/technetium-99m pyrophosphate overlap, whereas in the cases of permanent coronary occlusion, no technetium-99m pyrophosphate accumulation was seen. It is concluded that combined intracoronary thallium/technetium-99m pyrophosphate scintigraphy is helpful to predict myocardial salvage and areas of irreversible damage immediately after intracoronary thrombolysis.