Mark Friedman

Offsetting impact of thrombosis and restenosis on the occurrence of death and myocardial infarction after paclitaxel-eluting and bare metal stent implantation.

Background— Drug-eluting stents compared with bare metal stents (BMS) may increase late stent thrombosis (ST), although an accompanying increase in the rates of death and myocardial infarction (MI) has not been observed. We hypothesized that the prevention of restenosis-related adverse events by drug-eluting stents might offset some or all of the excess risk from ST. Methods and Results— We analyzed a pooled patient-level database from 4 prospective, double-blind trials in which 3445 patients were randomized to paclitaxel-eluting stents or BMS. The occurrence of death or MI within 7 days of ST or target lesion revascularization was assessed. With a median follow-up of 3.2 years, ST occurred in 34 patients (1.0%), 31 (91.1%) of whom sustained death or MI within 7 days. Target lesion revascularization was performed in 425 patients (12.3%), 15 (3.5%) of whom died or had MI within 7 days. ST occurred in 14 BMS and 20 paclitaxel-eluting stent patients, resulting in 12 and 19 deaths or MIs within 7 days, respectively. Target lesion revascularization was performed in 290 BMS and 135 paclitaxel-eluting stent patients, resulting in 11 and 4 deaths or MI events within 7 days, respectively. In total, 23 patients in both the BMS and paclitaxel-eluting stents groups died or had an MI event within 7 days of either ST or target lesion revascularization. Conclusions— ST, although infrequent, results in a high incident rate of death and MI, whereas the more frequent occurrence of target lesion revascularization is associated with a finite but lower rate of death and MI. The marked reduction in restenosis with drug-eluting stents compared with BMS may counterbalance the potential excess risk from late ST with drug-eluting stents.

The mitral valve orifice method for noninvasive two-dimensional echo Doppler determinations of cardiac output.

We developed and validated a mitral valve orifice method for Doppler cardiac output determination. In 15 open-chest dogs, cardiac output was controlled and measured by a roller pump interposed between the right atrium and pulmonary artery as a right-heart bypass. Left heart flows were measured in the open-chest dog model by Doppler measurements at the mitral valve orifice and compared not only to volume flow measured by the roller pump, but to electromagnetic flow meters as well. The maximum mitral valve orifice area was measured off short-axis two-dimensional echocardiographic views by planimetry. The maximal orifice was then adjusted for its diastolic variation in size by calculating a ratio of mean-to-maximal mitral valve separation on a derived M-mode echocardiogram. Flow was sampled parallel to mitral valve inflow in a four-chamber plane. The multiplication of mean flow throughout the cardiac cycle by the mean mitral valve area after correction for diastolic size variation yielded a cardiac output determination that could be compared to the roller pump measurement. Fifty-two cardiac output determinations over roller pump values of 1–5 1/min yielded a high correlation between roller pump flows and Doppler (r = 0.97 + 0.23 1/min). Our study shows that the mitral valve orifice provides an accurate site for Doppler cardiac output measurements.

The effect of variations of pulsed Doppler sampling site on calculation of cardiac output: an experimental study in open-chest dogs.

We measured aortic flow by two-dimensional Doppler echocardiography in an open-chest dog model to examine how variations in Doppler sample volume length and position influence aortic hemodynamic flow calculations. Fourteen dogs underwent right-heart bypass, in which venous return from the venae cavae drained by gravity to a reservoir. A variable-speed roller pump returned the blood to the pulmonary artery, fixing left-sided cardiac input and output. Echo Doppler measurements were performed using a 3.5-MHz transducer placed directly on the aortic arch to determine internal aortic cross-sectional area. The transducer was then directed to image the aortic arch for Doppler velocity measurements and the various sampling sites were investigated. Doppler cardiac output could then be determined for each of the various sample volumes over a range of known roller pump settings. Doppler velocity was analyzed using fast Fourier transform spectral analysis. Mean velocity over the cardiac cycle was obtained by planimetry of the area under the Doppler velocity curve with a minicomputer. Doppler-derived determinations of cardiac output achieved a correlation of r = 0.98–0.99 to values obtained by the roller pump over a range of cardiac outputs from 0.75–5 1/min. The standard error of the estimate was 0.2 I/min. In this laminar flow model, there was no difference between the predictive accuracy of any of the sampling sites over the range of roller pump flows. Our study shows that Doppler velocity measurements can be used to quantify aortic flow over a clinically useful range and that variations of sample length and position did not produce significant differences in calculated flows.

Experience with more than 100 total artificial heart implants.

OBJECTIVE The SynCardia Total Artificial Heart (SynCardia Systems Inc, Tucson, Ariz) has been used as a bridge to cardiac transplantation in 930 patients worldwide and in 101 patients in our program. Our experience with SynCardia Total Artificial Heart implantation documents its indications, safety, and efficacy. METHODS Data regarding preoperative condition, mortality, and morbidity have been reviewed and analyzed. RESULTS From January 1993 to December 2009, 101 patients had bridge to transplant procedures with the SynCardia Total Artificial Heart. Ninety-one percent of cases were Interagency Registry for Mechanically Assisted Circulatory Support profile 1, and the remaining 9% of cases were failing medical therapy on multiple inotropic medications. The mean support time was 87 days (median, 53 days; range, 1-441 days). Pump outputs during support were 7 to 9 L/min. Adverse events included strokes in 7.9% of cases and take-back for hemorrhage in 24.7% of cases. Survival to transplantation was 68.3%. Causes of death of 32 patients on device support included multiple organ failure (13), pulmonary failure (6), and neurologic injury (4). Survival after transplantation at 1, 5, and 10 years was 76.8%, 60.5%, and 41.2%, respectively. The longest-term survivor is currently alive 16.4 years postimplantation. CONCLUSIONS These patients were not candidates for left ventricular assist device therapy and were expected to die. The SynCardia Total Artificial Heart offers a real alternative for survival with a reasonable complication rate in appropriate candidates who otherwise might have been assigned to hospice care.

Clinical correlations in patients with acute myocardial infarction and left ventricular thrombus detected by two-dimensional echocardiography

Eleven of forty-nine patients with acute myocardial infarction had left ventricular thrombus identified by two-dimensional echocardiography. The patients with thrombi had a greater incidence of transmural infarction, high-grade ventricular ectopy on ambulatory monitoring and lower radionuclide ejection fractions than the patients without thrombi. Most of the patients were receiving full-dose heparin and/or warfarin anticoagulation from the time of admission to the hospital. Thus the thrombi either developed prior to hospital admission or developed during anticoagulation therapy. Two patients with thrombi had peripheral emboli complicating their infarction. One of these patients was undergoing anticoagulation at the time of his embolus.

Left ventricular systolic and diastolic function in hyperthyroidism

In order to assess the effect of hyperthyroidism on systolic and diastolic function of the left ventricle, M-mode echocardiograms and systolic time intervals were obtained in 13 patients while they were clinically hyperthyroid and again when they were euthyroid following radioactive iodine therapy. Echocardiographic tracings of the septum and left ventricular posterior wall were digitized and analyzed to provide the maximum velocity of shortening and maximum velocity of lengthening. These velocities were normalized for left ventricular diastolic dimension. The left ventricular minor axis fractional shortening and the normalized maximum velocity of shortening were both increased during the hyperthyroid state. The normalized maximum velocity of lengthening, a measure of diastolic left ventricular function, was also increased during the hyperthyroid state when compared to the euthyroid state. The preejection period index and the preejection period/left ventricular ejection time ratio were lower when the patients were hyperthyroid than when they were euthyroid. These data confirm the increased inotropic state and demonstrated increased diastolic relaxation velocities of the hyperthyroid left ventricle.

Diagnostic value of exercise-induced S-T segment depression in patients with right bundle branch block

Abstract The sensitivity of submaximal exercise testing in detecting coronary artery disease in patients with right bundle branch block is not known. Thirty patients were identified who had right bundle branch block, submaximal treadmill exercise tests and selective coronary angiography. Eighteen of these patients were found to have significant coronary artery disease. Treadmill exercise testing was associated with S-T segment depression limited to leads V 1 to V 3 in three patients with coronary artery disease, whereas S-T segment depression was noted in leads V 4 to V 6 in eight patients, all of whom had multivessel coronary artery disease. Among patients without significant coronary artery disease, six had S-T segment depression limited to leads V 1 to V 3 during exercise testing. In this patient population, composed predominantly of men with symptoms of ischemic heart disease, the 12 lead submaximal treadmill exercise test had a sensitivity rate of 69 percent and a specificity rate of 45 percent in detecting coronary artery disease in the presence of right bundle branch block. The specificity of the treadmill test appears to be greater if S-T depression is recorded in leads V 4 to V 6 . S-T segment depression limited to leads V 1 to V 3 often represents a false positive exercise test.

Accuracy of M mode echocardiographic measurements of the left ventricle.

Abstract M mode echocardiography provides quantitative information regarding the dimensions of the left ventricle. To compare left ventricular dimensions obtained by several methods from the M mode echocardiogram with actual dimensions, M mode echocardiograms of the inferventricular septum and left ventricular posterior wall were recorded simultaneously with sonomicrometer crystal signals of the left ventricular minor axis dimension in 12 instrumented open chest dogs. End-diastolic dimension from the M mode echocardiogram was measured (1) at the onset of the QRS complex, (2) at the peak of the R wave of the electrocardiogram, and (3) as the largest diameter. End-systolic dimension was measured from the M mode echocardiogram (1) at the nadir of septal motion, (2) at the peak of posterior wall motion, and (3) as the smallest dimension. End-diastolic dimension measured either at the onset of the QRS complex or at the peak of the R wave did not differ from that measured from the sonomicrometer crystal signals. However, end-diastolic dimension measured as the largest diameter was significantly larger than that measured from the sonomicrometer crystal signals (p On the M mode echocardiogram, end-diastolic dimension is most accurately measured at the onset of the QRS complex or at the peak of the R wave of the electrocardiogram. End-systolic dimension is most accurately measured at the nadir of posterior motion of the interventricular septum when septal motion is normal. These data support the recommendations of The American Society of Echocardiography on attempts to quantitate left ventricular minor axis dimensions from the M mode echocardiogram.

A new technique for noninvasive evaluation of femoral arterial and venous anatomy before and after percutaneous cardiac catheterization in children and infants

A new ultrasonic method was applied to image the femoral artery and vein in children for evaluation of short- and long-term effects of cardiac catheterization with femoral percutaneous cannulation. Sixty-six children and infants (aged 5 days to 20 years) were studied with a 9 megahertz electronically focused real time scanner. Adequate studies were obtained in 46 patients before catheterization, in 26 of 30 short-term follow-up studies and in 14 long-term follow-up studies. Femoral arterial size could be quantitatively measured at the inguinal ligament and a correlation existed between imaged femoral arterial diameter and body weight (r = +0.82) or body surface area (r = +0.80). Short-term follow-up ultrasonic imaging studies allowed diagnosis of spasm and other complications of percutaneous femoral arterial puncture. Long-term follow-up studies were performed 4 months to 3 years after catheterization in 14 patients who had no complications recorded at the time of catheterization. These revealed significant differences between vessels on the catheterized and uncatheterized (control) sides in only 3 of the 14. High resolution ultrasonic imaging can provide anatomic and functional information about femoral arteries and veins and appears to be of assistance in planning cardiac catheterization and in studying the short- and long-term effects of percutaneous femoral cannulation.

Two-dimensional echocardiography and B-mode ultrasonography for the diagnosis of loculated pericardial effusion.

Two cases of loculated pericardial effusion resulting in cardiac tamponade are presented. The loculated nature and extent of the effusion was best defined by two-dimensional echocardiography or B- mode ultrasonography. Cross-sectional images should probably be obtained in all cases of suspected loculated pericardial effusion and in patients in whom the interpretation of the M-mode echocardiogram is equivocal as to the presence or absence of pericardial effusion.