Stinson Eb

Clinical experience, complications, and survival in 70 patients with the automatic implantable cardioverter/defibrillator.

Seventy patients received the automatic implantable defibrillator, five original devices and 72 modified second-generation devices using only bipolar rate sensing and delivering an R wave synchronous cardioverting/defibrillating shock, for either ventricular tachycardia or fibrillation. The primary clinical arrhythmia was sustained ventricular tachycardia in 32 patients, ventricular fibrillation in 20 patients, and both ventricular tachycardia and fibrillation in 18 patients. Before implantation of the device the patients had survived 3.1 +/- 2.3 arrhythmic episodes, including 1.9 +/- 1.7 cardiac arrest, and had received 4.0 +/- 2.1 antiarrhythmic drugs without improvement. Sixty-eight patients ultimately received devices. After a follow-up period of 8.9 +/- 7.7 months (range 1 to 33), 37 patients received a total of 463 discharges. Inability to determine the precise reason for most discharges and the unpleasant nature of the discharges were the major clinical problems encountered. Complications included postoperative death (one patient), lead problems (six patients), inadequate energy requiring explanation (two patients), and pocket infection (one patient. Life-table analysis revealed 6 and 12 month cardiovascular survival of 95.0% and 89.9% and sudden death survival of 98.2%. In our experience, survival with the automatic implantable cardioverter/defibrillator exceeds that with other forms of therapy.

Intracoronary ultrasound in cardiac transplant recipients. In vivo evidence of "angiographically silent" intimal thickening.

BackgroundAccelerated coronary atherosclerosis is a major factor limiting allograft longevity in cardiac transplant recipients. Histopathology studies have demonstrated the insensitivity of coronary angiography for detecting early atheromatous disease in this patient population. Intracoronary ultrasound is a new imaging techniquse that provides characterization of vessel wall morphology. The purpose of this study was to compare in vivo intracoronary ultrasound with angiography in cardiac transplant recipients. Methods and ResultsThe left anterior descending coronary artery was studied with intracoronary ultrasound in 80 cardiac transplant recipients at the time of routine screening coronary angiography 2 weeks to 13 years after transplantation. A mean and index of intimal thickening were obtained at four coronary sites. Intimal proliferation was classified as minimal, mild, moderate, or severe according to thickness and degree of vessel circumference involved. Twenty patients were studied within 1 month of transplantation and had no angiographic evidence of coronary disease. An intimal layer was visualized by ultrasound in only 13 of these 20 presumably normal hearts. The 60 patients studied 1 year or more after transplantation all had at least minimal intimal thickening. Twenty-one patients (35%) showed minimal or mild, 17 (28%) moderate, and 21 (35%) severe thickening. Forty-two of these 60 patients had angiographically normal coronary arteries, 21 (50%) of whom had either moderate or severe thickening. All 18 patients with angiographic evidence of coronary disease had moderate or severe intimal thickening, but there was no statistically significant difference in intimal thickness or index when compared with the patients with moderate or severe proliferation and normal angiograms (thickness, 0.53±0.35 mm versus 0.64±0.30 mm, p = NS; index, 0.28±0.10 versus 0.34±0.10, p = NS). ConclusionsThe majority of patients 1 or more years after cardiac transplantation have ultrasound evidence of intimal thickening not apparent by angiography. Intracoronary ultrasound offers early detection and quantitation of transplant coronary disease and provides characterization of vessel wall morphology, which may prove to be a prognostic marker of disease.

Treatment of patients with aortic dissection presenting with peripheral vascular complications.

The Incidence of peripheral vascular complications in 272 patients with aortic dissection during a 25-year span was determined, as was outcome after a uniform, aggressive surgical approach directed at repair of the thoracic aorta. One hundred twenty-eight patients (47%) presented with acute type A dissection, 70 (26%) with chronic type A, 40 (15%) with acute type B, and 34 (12%) with chronic type B dissections. Eighty-five patients (31%) sustained one or more peripheral vascular complications: Seven (3%) had a stroke, nine (3%) had paraplegia, 66 (24%) sustained loss of a peripheral pulse, 22 (8%) had Impaired renal perfusion, and 14 patients (5%) had compromised visceral perfusion. Following repair of the thoracic aorta, local peripheral vascular procedures were unnecessary in 92% of patients who presented with absence of a peripheral pulse. The operative mortality rate for all patients was 25% ± 3% (68 of 272 patients). For the subsets of individuals with paraplegia, loss of renal perfusion, and compromised visceral perfusion, the operative mortality rates (± 70% confidence limits) were high: 44% ± 17% (4 of 9 patients), 50% ± 11% (11 of 22 patients), and 43% ± 14% (6 of 14 patients), respectively. The mortality rates were lower for patients presenting with stroke (14% ± 14% [1 of 7 patients]) or loss of peripheral pulse (27% ± 6% [18 of 66 patients]). Mul-tivariate analysis revealed that impaired renal perfusion was the only peripheral vascular complication that was a significant independent predictor of Increased operative mortality risk (p = 0.024); earlier surgical referral (replacement of the appropriate section of the thoracic aorta) or more expeditions diagnosis followed by surgical renal artery revascularization after a thoracic procedure may represent the only way to Improve outcome in this high-risk patient subset. Early, aggressive thoracic aortic repair (followed by aortic fenestration and/or abdominal exploration with or without direct visceral or renal vascular reconstruction when necessary) can save some patients with compromised visceral perfusion; however, once visceral Infarction develops, the prognosis Is also poor. Increased awareness of these devastating complications of aortic dissection and the availability of better diagnostic tools today may Improve the survival rate for these patients In the future. The initial surgical procedure should Include repair of the thoracic aorta in most patients.

Measurement of midwall myocardial dynamics in intact man by radiography of surgically implanted markers.

Tiny radiopaque helices (0.85 × 1.5 mm) of pure tantalum wire were implanted by means of a simple insertor instrument into the left ventricular myocardium in 24 patients at the time of cardiac surgery. The markers were positioned in such a way as to outline the profile of the left ventricle when viewed in a 30° right anterior oblique projection. Biplane studies showed that all markers could be placed very nearly in a plane using the surface anatomy of the heart as a guide to implantation. Implantation of markers required approximately two minutes. No intraoperative or postoperative complications ascribable to the markers have occurred. They remain firmly in place and allow acquisition of a noninvasive ventriculogram at any time after surgery. The dynamic geometry of the left ventricle was determined by analysis of cineradiograms of these markers. Utilization of a single-plane (right anterior oblique) cineradiogram to obtain measurements of major transverse ventricular diameters, mean circumferential shortening, and circumferential shortening velocity results in underestimation of lengths by 1.4%, overestimation of shortening by 1.2% of end-diastolic length, and overestimation of velocity by 0.05 circ/sec, when compared with values obtained simultaneously from biplane cineradiograms.

Alterations in left ventricular twist mechanics with inotropic stimulation and volume loading in human subjects.

BACKGROUND Left ventricular (LV) twist, the longitudinal gradient of circumferential rotation about the LV long axis, may play an important role in the storage of potential energy at end systole and its subsequent release as elastic recoil during early diastole; however, the effects of load and inotropic state on LV systolic twist and diastolic untwist in human subjects have not previously been characterized. METHODS AND RESULTS Six cardiac transplant recipients with 12 implanted radiopaque midwall LV myocardial markers were studied 1 year after transplantation. Biplane cinefluoroscopic marker images and LV pressure were recorded during control conditions and after afterload augmentation (methoxamine, 5 to 10 micrograms.kg-1 x min-1), inotropic stimulation (dobutamine, 5 micrograms.kg-1 x min-1), and preload augmentation (volume loading with normal saline). Systolic twist dynamics were assessed by maximum twist (Tmax[rad/cm]), peak negative twist rate (-dT/dtmin[rad.cm-1 x s-1]), and the slope of the twist normalized-ejection fraction relation (T-nEFR, Msys[rad/cm]) during systole. Diastolic untwist was assessed by the peak positive untwist rate (+dT/dtmax [rad.cm-1 x s-1]) and the slopes (rad/cm) of the T-nEFR during early diastole (Mear-dia) and mid diastole (Mmid-dia). Compared with control values, LV pressure and volume loading had no significant effect on Tmax, -dT/dtmin, or Msys; however, inotropic stimulation significantly increased all parameters describing systolic twist (Tmax: -0.10 +/- 0.03 versus -0.06 +/- 0.02 rad/cm, P < .001; -dT/dtmin: -0.72 +/- 0.19 versus -0.44 +/- 0.22 rad.cm-1 x s-1, P < .001; Msys: -0.10 +/- 0.03 versus -0.06 +/- 0.01 rad/cm, P < .001). Pressure loading had no effect on early diastolic untwisting; however, dobutamine significantly increased M(ear)-dia (-0.24 +/- 0.06 versus -0.13 +/- 0.04 rad/cm, P < .0001) and +dT/dtmax (0.78 +/- 0.24 versus 0.45 +/- 0.16 rad.cm-1 x s-1, P < .001). Conversely, volume loading significantly decreased M(ear)-dia (-0.08 +/- 0.04 versus -0.13 +/- 0.04 rad/cm, P < .05). M(ear)-dia correlated directly with LV contractile state (as assessed as maximum dP/dt, r = .60, P < .0001) and inversely with end-systolic volume (r = -.87, P < .0001) but was unrelated to stroke volume (r = .08, P = .30) or LV afterload (estimated as effective arterial elastance, r = .08, P = .29). Mmid-dia did not change during any intervention. CONCLUSIONS In conscious human transplant patients, (1) pressure and volume loading do not affect systolic LV twist; (2) dobutamine augments systolic twist and early diastolic untwisting, suggesting more end-systolic potential energy storage and early diastolic elastic recoil with enhanced inotropic state; (3) volume loading decreases early diastolic untwisting, possibly reflecting diminished recoil forces after preload augmentation associated with larger end-systolic volumes (ESV); and (4) M(ear)-dia correlates strongly with ESV (in an inverse fashion), and less strongly, but directly, with LV dP/dtmax.

Cardiorespiratory responses of cardiac transplant patients to graded, symptom-limited exercise.

SUMMARYThe electrocardiographic and ventilatory responses of 15 denervated heart patients who had undergone cardiac transplantation and 14 age-matched, normally innervated men were compared to assess the pattern of response to graded treadmill exercise. A 5-minute postexercise venous lactate sample was also obtained. Respiratory exchange ratio and ventilation (VE) were higher in denervated patients than in normals during submaximal exercise. Peak values (normals vs denervated) for heart rate (172 vs 159 beats/min), blood pressure (189 vs 167 mm Hg), oxygen uptake (37 vs 25 ml/kg/min), oxygen pulse (0.22 vs 0.16 ml/kg/beat) and work time (26.2 vs 18.0 minutes) were higher in normals than in cardiac transplant recipients. Peak ventilatory equivalent (2.14 vs 3.13 1/ml/kg) and lactate values were higher for transplants than for normal subjects, but there were no significant intergroup differences in peak VE or in the respiratory exchange ratio. In cardiac transplant recipients, work time correlated inversely with a measure of rejection history (r = −0.59, p < 0.01). The response of cardiac transplant recipients to treadmill work differs from that of normal men and reflects a diminished ability to meet the oxygen demands of the exercising periphery.

Detection of coronary atherosclerosis in young adult hearts using intravascular ultrasound.

BackgroundCoronary atherosclerosis has been demonstrated in young adults by postmortem pathology. Angiographic evaluation of coronary disease in young adults is limited by ethical issues and the insensitivity of angiography for detecting early pathology. Catheter-based intracoronary ultrasound has proven useful both in detecting and quantitating coronary disease, but the ultrasound appearance of young, angiographically normal, coronary arteries has not been well defined. Methods and ResultsTwenty-five subjects were examined with intracoronary ultrasound within 1 month of cardiac transplantation. Mean age of the donor hearts was 28 years (range, 14–43 years). Measurements of an index of intimal thickening were obtained at four left anterior descending coronary artery sites in each patient. All study patients had angiographically normal coronary arteries. Ultrasound in 14 subjects demonstrated a three-layered appearance of the coronary vessel wall with a mean intimal index of 0.16±0.07. The other 10 subjects, including all donors under the age of 25 years, had coronary vessel wall layers too thin to be imaged separately at the 30-MHz sound frequency. Five subjects had ultrasound evidence of focal intimal thickening greater than 500 μm. The donors of these hearts each had risk factors for coronary artery disease. Two subjects died within 5 weeks of their ultrasound study. Histological measurements of the vessel wall layers were similar to the corresponding ultrasound values. ConclusionsThis study provides a reference for the intravascular ultrasound appearance ofyoung adult coronary arteries and confirms pathology findings that young subjects with angiographically normal vessels have a range of coronary intimal thickening, which includes occasional evidence of focal, early atheromatous lesions.

Evaluation of methods for quantitating left ventricular segmental wall motion in man using myocardial markers as a standard.

Radiopaque markers were implanted in the left ventricular myocardial midwall in 58 patients and studied in the 30° right anterior oblique projection by computer-aided fluoroscopy. Marker motion was used as a standard of segmental wall motion against which the accuracy of five methods for measuring left ventricular wall motion was assessed: two methods using hemiaxial measurements in rectangular coordinates, two using radial measurements in polar coordinates (all with frame-by-frame axial reindexing) and one using radial measuremehts in fixed external polar coordinates. The latter method showed significantly les error (25.9%, p < 10–6) in measuring midwall marker motion than the other four methods (range 42.5–47.5%) in the group as a whole and in subgroups that had abnormalities of posterior, apical and anterior wall motion. This method also had the best correlation of marker motion and motion of adjacent endocardial border (of the overall left ventricle and the posterior, apical, and anterior walls separately) as visualized by ventriculography in 29 patients. The bulk of the reduction in error using this method was due to the use of a fixed external reference system, with a small additional increment of error removed by proper selection of the polar origin at a point 69% of the distance from the anterolateral edge of the aortic valve to the ventricular apex at endsystole.

Defective in vitro suppressor cell function in idiopathic congestive cardiomyopathy.

Because abnormalities of the immune system may be involved in the pathogenesis of idiopathic congestive cardiomyopathy (ICCM), we studied suppressor cell function in patients with ICCM. Previously described in vitro techniques were modified for optimal demonstration of concanavalin A (con A)-inducible suppressor activity by peripheral blood mononuclear cells (PBM). Baseline responses in the mixed leukocyte reaction (MLR) were similar for PBM from 16 normal subjects, eight patients with end-stage coronary artery disease (CAD), and 18 patients with ICCM. In the presence of autologous, con A-treated PBM, MLR responses were significantly suppressed for normals (geometric mean disintegrations/min decreasing from 36,308 to 4677; p < 0.001) and for CAD patients (25,703 decreasing to 50l1;p < 0.001). In contrast, autologous, conc A-treated PBM from patients with ICCM failed to suppress MLR responses (30,902 increasing to 44,688; p < 0.005). Similar results were observed in mitogen stimulation experiments. Con A-treated PBM from a normal subject suppressed the MLR response of PBM from an ICCM patient. The failure of con A-treated PBM to inhibit in vitro immune responses may reflect an in vivo defect in suppressor cell function in patients with ICCM.

SERIAL TRANSVENOUS BIOPSY OF THE TRANSPLANTED HUMAN HEART IMPROVED MANAGEMENT OF ACUTE REJECTION EPISODES

Abstract One hundred and nineteen percutaneous transvenous cardiac biopsy procedures have been performed in sixteen patients after heart transplantation. Serial cardiac biopsies have been used to monitor acute rejection episodes in twelve of these patients, eleven of whom are alive 1-13 months after transplantation. 37 acute rejection episodes were diagnosed from histological examination of the biopsy specimens, and 35 of these episodes were successfully reversed by augmentation of immunosuppression. Reversal of acute cardiac allograft rejection was confirmed by the restoration of histologically normal endomyocardium. Serial percutaneous transvenous endomyocardial biopsy is simple, safe, and effective. It is readily accepted by patients, and represents an important advance in human cardiac transplantation.