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Biomedical subjects

H Laks

Publications and source records attributed to H Laks.

At least 235 records · Page 13Linked to original sources
PubMed1986

Use of a venous assist device after repair of complex lesions of the right heart.

Sixteen patients underwent hemodynamic evaluation of a venous assist device after complex operations on the right side of the heart. The device consists of an inflatable abdominal binder attached to a Jobst extremity pump causing intermittent external compression of the abdomen. In addition, six of these patients were evaluated using total lower body compression for comparison. Modifications of the Fontan procedure were performed in 14 patients, mitral valve anuloplasty and tricuspid valve replacement in 1 patient and reconstruction of the right ventricular outflow tract for treatment of pulmonary atresia with intact septum in 1 patient. The patients' ages ranged from 23 months to 31 years (mean 10.7 +/- 1.8 years). Systemic blood pressure, right and left atrial pressures, heart rate and arterial-mixed venous oxygen saturation difference were recorded in each patient with and without the device in place. With the venous assist device, mean systolic pressure increased from 95 +/- 4 to 122 +/- 3 mm Hg (p less than 0.05) and diastolic pressure rose from 57 +/- 3 to 70 +/- 3 mm Hg (p less than 0.05). Left atrial pressure increased from 7 +/- 1 to 15 +/- 1 mm Hg and right atrial pressure from 15 +/- 1 to 23 +/- 1 mm Hg (both p less than 0.05). In addition, arterial-mixed venous oxygen saturation difference decreased from 29% without the device to 23% with the device in place (p less than 0.05). Total lower body compression gave similar results to intermittent abdominal compression alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Subaortic obstruction in complex congenital heart disease: management by proximal pulmonary artery to ascending aorta end to side anastomosis.

Six patients with univentricular heart and one patient with d-transposition of the great arteries had transection of the main pulmonary artery with an end to side anastomosis of the main pulmonary artery to the ascending aorta to relieve subaortic obstruction. Two operations were performed as a palliative procedure within the first 6 months of life and five were performed as part of a definitive repair (four modified Fontan procedures and one repair of transposition of the great arteries with ventricular septal defect). There was one surgical death (14%) occurring 1 day postoperatively from low cardiac output. The remaining six patients are doing well 1 to 19 months postoperatively (mean 11.4 months). The proximal pulmonary artery to ascending aorta end to side anastomosis is an effective means of bypassing subaortic obstruction associated with complex congenital heart disease.

Aorta↗
PubMed1985

Early and late results in the treatment of patients with pulmonary atresia and intact ventricular septum.

The courses of 22 consecutive patients with pulmonary atresia and intact ventricular septum who underwent surgery between 1977 and 1984 were reviewed. This included 18 patients undergoing an initial surgical palliation, and four patients referred for a definitive procedure. A surgically oriented classification based on the degree of right ventricular hypoplasia was developed and applied. Three groups were identified and were termed the mild, moderate, and severe hypoplasia groups. Those in the mild and moderate groups had mild or moderate right ventricular and tricuspid hypoplasia with well-developed right ventricular outflow tracts and were therefore acceptable candidates for procedures to create an opening between the right ventricle and pulmonary artery. Those in the severe hypoplasia group and severe hypoplasia of the tricuspid valve, the right ventricle, and the right ventricle outflow tract so that attempts at establishing continuity with the pulmonary artery were thought to be unlikely to succeed. There were three patients with mild, 11 with moderate, and eight with severe hypoplasia. In the mild hypoplasia group, all three patients initially underwent valvotomy alone, but two required a shunt in the early postoperative period. In the moderate hypoplasia group, all patients underwent a valvotomy and received a central shunt with a snare, which allowed subsequent adjustment of pulmonary flow without thoracotomy in four patients. In the severe hypoplasia group, five patients received a shunt alone and one underwent valvotomy with atrial septectomy. This last patient represents the only early (less than 30 days) death in the series (6% mortality).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Vessel Prosthesis↗
PubMed1985

The effects of myocardial ischemia followed by reperfusion on perfused coronary capillarity.

To determine the effects of ischemia and reperfusion on myocardial perfused capillary density, rat hearts were excised, kept ischemic for thirty minutes then reperfused with blood from a support animal. Control hearts were isolated and perfused for either 10 or 60 minutes before injection of a vascular marker (Monastral Blue-blood mixture, 30 sec at 100 mmHg). The ischemic hearts were perfused with Blue after 10 minutes of reperfusion. The perfused capillary density (theta) and capillary/fiber ratio (C/F) were measured from frozen transverse sections of the left ventricle. For 10- and 60-minute control hearts, the epicardial theta values were 2324 +/- 476 caps/mm2 and 2378 +/- 330 SD. The endo/epi theta ratio was not significantly less than unity for either control group. For the ischemic group, theta was significantly decreased both in the epicardium (707 +/- 515 caps/mm2) and endocardium (130 +/- 30 caps/mm2) (p less than 0.05). The endo/epi theta ratio was significantly less than unity for the ischemic group (P less than 0.05). The C/F ratio analysis yielded the same results. The decrease in both theta and CF ratio indicate that 30 minutes of ischemia followed by 10 minutes of reperfusion caused a marked "No-reflow" phenomena in isolated, supported hearts. The No-reflow was most pronounced in the endocardium.

Animals↗
PubMed1984

Incidence and significance of early pericardial effusions after cardiac surgery.

Echocardiography (echo) is frequently performed postoperatively to evaluate patients suspected of having cardiac tamponade or pericarditis. The overall incidence and significance of echocardiographic pericardial effusions (PE) early after cardiac surgery are unknown. Therefore, M-mode and 2-dimensional (2-D) echo were used to study 39 stable patients 4 to 10 days after cardiac surgery. Twenty-two patients (56%) had unequivocal moderate-to-large PEs. PEs were identified on serial chest x-rays in only 6 patients. PEs were significantly more common after heavy postoperative bleeding, and occurred in 16 of 19 patients with more than 500 ml of total chest tube output; only 6 of 20 patients with chest tube output less than 500 ml had PE. There was no correlation of PE by echo with pericardial friction rubs, chest pain or atrial arrhythmias. Elevated erythrocyte sedimentation rate did not correlate with PE by echo or clinical pericarditis. In 1 of 22 patients with PE, tamponade developed, and the patient required reoperation on day 5; the other 21 were discharged without related therapy. Thus, early postoperative PEs are common and related to postoperative bleeding. Because they do not correlate with symptoms of pericarditis and rarely lead to tamponade, their identification is usually of limited clinical significance.

Adult↗
PubMed1984

Improved myocardial recovery from ischemia. Treatment with low-dose adenosine triphosphate-magnesium chloride.

To evaluate the effects of adenosine 5-triphosphate-magnesium chloride (ATP-MgCl2) on myocardial function following ischemia, mongrel dogs were placed on cardiopulmonary bypass with separate coronary perfusion pressures at 80 mm Hg. An intraventricular balloon was used to assess cardiac function as the area under the pressure-volume curve (PV), compliance (C), and cardiac contractility (dP/dT). Control measurements were made of coronary flow (Q), myocardial oxygen consumption and PV, C, and dP/dT. Myocardial ischemia was then induced for 45 minutes, followed by reperfusion (R). In group 1 (n = 5), no ATP-MgCl2 was infused into the coronary perfusion line. In group 2 (n = 5), low-dose ATP-MgCl2 (0.13 mg/min/kg) was infused during the first 30 minutes of reperfusion (R0 to R30), and in group 3 (n = 5), high-dose ATP-MgCl2 (3.2 mg/min/kg) was infused from R0 to R30. Use of ATP-MgCl2 therapy produced marked coronary vasodilation. After 20 minutes of reperfusion (R20), coronary resistance was 81% +/- 12%, 55% +/- 15%, and 31% +/- 3% of control in groups 1, 2, and 3, respectively. The high-dose ATP-MgCl2 (group 3) caused a marked systemic hypotension, but the low-dose ATP-MgCl2 (group 2) did not. After 75 minutes of reperfusion (R75), compliance was decreased in all groups. In groups 1 and 3, both function (PV) and dP/dT were significantly decreased. However, for group 2 (low-dose ATP-MgCl2), function (PV), and dP/dT were not different from the control group, indicating an excellent recovery. Thus, at low doses, ATP-MgCl2 appears to be a promising adjunct to the treatment of the ischemic myocardium.

Adenosine Triphosphate↗
PubMed1984

An improved method of pulmonary artery banding.

Banding of the pulmonary artery is a difficult procedure that often requires band readjustment. A new technique for placing and adjusting pulmonary artery bands using an adjustable snare is presented, together with cases illustrating its application.

Heart Defects, Congenital↗
PubMed1984

Thrombolytic therapy for superior vena caval thrombosis following superior vena cava-pulmonary artery anastomosis.

Immediate postoperative thrombosis of left superior vena cava-left pulmonary artery anastomosis in a modified Fontan procedure for single ventricle and pulmonary artery stenosis is described. Before thrombolytic therapy with streptokinase is initiated, confirmation of thrombosis by venography is mandatory to lessen the risk of cardiac tamponade or hemothorax. By this technique major surgical intervention is avoided, but close attention to the dose of streptokinase and the coagulation profile is essential. Measures to be taken if bleeding occurs with streptokinase therapy are described.

Adult↗
PubMed1984

Surgical correction of pulmonary atresia and ventricular septal defect with large systemic-pulmonary collaterals.

A two-stage surgical procedure was performed in a young adult with pulmonary atresia and a ventricular septal defect with upper lobe pulmonary artery flow from confluent central pulmonary arteries and lower lobe pulmonary blood flow originating from two large systemic-pulmonary collaterals. Initially a Dacron Y graft was anastomosed between the ascending aorta and the collaterals and a graft to the left pulmonary artery. At the second operation, continuity was established between the right ventricle and the Y graft by using a valved Dacron conduit and the ventricular septal defect was closed.

Adult↗
PubMed1984

Chronic norepinephrine infusion and insulin and glucagon secretion in the dog.

The effect of epinephrine on glucose homeostasis has been studied extensively in many species, but there is little data on the effects of another catecholamine, norepinephrine. This study was designed to examine the alterations that occur in insulin and glucagon secretion during a chronic low-dose infusion of norepinephrine in free-roaming dogs. A total of four intravenous glucose tolerance tests and insulin-induced hypoglycemia tests were performed on each of five dogs infused with norepinephrine (1.4 g/min) for 3 mo and on each of eight control dogs. The infusion resulted in a threefold increase in plasma norepinephrine without a significant effect on blood pressure. Fasting serum glucose was elevated significantly in the norepinephrine-infused dogs [102.4 +/- 2.1 vs. 92.8 +/- 1.7 (SE) mg/100 ml]. Fasting plasma glucagon was elevated by the norepinephrine infusion (58.4 +/- 7.6 vs. 31.3 +/- 3.1 pg/ml), whereas fasting serum insulin was inhibited (12.3 +/- 1.3 vs 16.8 +/- 1.7 U/ml). Glucagon secretion in response to hypoglycemia was markedly enhanced in the infused dogs compared with controls. It has been reported that the infusion of norepinephrine in humans will inhibit insulin secretion and increase serum glucose concentrations but have no effect on serum glucagon concentrations. The stimulation of glucagon by norepinephrine has been demonstrated in the isolated, perfused canine pancreas but has not been reported previously in the free-roaming dog.

Adrenal Glands↗
PubMed1984

Systemic venous and pulmonary arterial flow patterns after Fontan's procedure for tricuspid atresia or single ventricle.

Despite increasing use of Fontan or modified Fontan repairs, the comparative hemodynamic efficacy of different types of connections are unresolved. Accordingly, we undertook a prospective study designed to determine postoperative flow patterns after Fontan's operation. Seven subjects had tricuspid atresia and eight had single ventricle. Ages ranged from 5 to 38 years (mean 16.4). Ten subjects had nonvalved right atrial-to-pulmonary arterial connection, and four had nonvalved right atrial-to-right ventricular communication. A valved conduit established continuity between the right atrium and right ventricle in one subject. Doppler flow profiles were recorded in the pulmonary artery and in the superior and inferior venae cavae of each. A reference electrocardiogram was used for timing purposes. In 14 patients, forward flow in the pulmonary artery was biphasic. Flow began at the end of the T wave (early ventricular diastole), peaked at or before the P wave (atrial systole), and returned to baseline by the peak of the R wave. Forward flow recommenced at the peak of the R wave (ventricular systole) and returned to baseline at the end of the T wave. Flow in the superior vena cava varied, and could not be recorded in three subjects. Between the end of the P wave and peak of the R wave (atrial systole) flow was reversed in eight, absent in three, and forward in one patient. Forward flow occurred between the peak of the R wave and the end of the T wave and was either continuous or biphasic. Fourteen patients had adequate studies of inferior vena cava flow; reversed flow during atrial systole occurred in 10 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Combined valve replacement and myocardial revascularization.

Combining valve replacement with coronary artery bypass (CABG) for significant concomitant disease remains a controversial subject. To determine the operative results following combined valve replacement and CABG, we evaluated 201 patients seen consecutively between July 1977 and June 1982. CABG for vessels with greater than 70% stenosis was performed with aortic valve replacement in 106 patients, with mitral valve replacement in 82, and with aortic and mitral valve replacement in 13. There were 143 men and 58 women; the mean age was 67 years. Nine operative deaths (8.5%) occurred with aortic valve replacement and CABG: 5 of 25 (20%) when cardioplegia was not used and 4 of 81 (4.9%) with cardioplegia (p less than 0.01). The operative mortality rate for isolated aortic valve replacement without coronary disease during the same period was 5.9% (10 of 168). The late actuarial survival rate is similar for aortic valve replacement alone or aortic valve replacement and CABG. There were no operative deaths among patients having undergone aortic and mitral valve replacement and CABG; the rate was 15% (9 of 60) in patients having undergone aortic and mitral replacement and CABG. The operative mortality rate was 21.9% for mitral valve replacement and CABG (18 of 82). Rheumatic disease was present in 14 of these patients, two of whom had early deaths (14.3%), both after repeat mitral operations; 11 mitral valve replacements and CABG were done for degenerative mitral regurgitation with no deaths, and the remaining 57 patients had ischemic mitral regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1984

Experience with the Fontan procedure.

From 1975 to the present, 45 patients have undergone modifications of the Fontan procedure for complex congenital heart disease. There were 30 males and 15 females ranging in age from 2 to 38 years (mean 13 years). Primary diagnoses were tricuspid atresia in 19, univentricular heart in 24, and pulmonary atresia with intact ventricular septum in two. Right atrial-pulmonary arterial connections were performed in 32 patients, 11 with conduits (seven with valves and four without) and 21 by direct anastomosis with patch augmentation. Right atrial-right ventricular connections were made in 13 patients, six with valved conduits and seven without conduits. Follow-up ranged from 0.1 to 9 years, with a mean of 2.3 years. There were three early deaths (less than 30 days) (7%) and two late deaths (5%) in this series, all in patients with a univentricular heart. The late deaths were both related to venous hypertension. A venous assist device was used in eight patients in the immediate postoperative period and was effective in improving cardiac output and reducing fluid accumulation. Postoperative Doppler flow studies in 15 patients revealed biphasic pulmonary artery flow in all without distinction between the type of connection or the presence of a valve. Cardiac catheterization was performed in 16 patients a mean of 14 months postoperatively (range 1 to 42 months) and revealed a reduced cardiac index at rest. Exercise testing in eight patients demonstrated a marked rise in right atrial pressure with a reduced rise in the cardiac index, even in those without functional limitations. With a mean follow-up of 2.3 years, 78% of patients were in New York Heart Association Class I, 17% in Class II, and 5% in Class III. We conclude that the Fontan procedure is an excellent operation in carefully selected patients with tricuspid atresia and other forms of complex congenital heart disease.

Adolescent↗