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Biomedical subjects

H Laks

Publications and source records attributed to H Laks.

At least 253 records · Page 14Linked to original sources
PubMed1984

Management of pulmonary arteriovenous fistulas after superior vena cava-right pulmonary artery (Glenn) anastomosis.

Pulmonary arteriovenous fistulas developed following a superior vena cava-right pulmonary artery shunt in a patient with cyanotic heart disease. An axillary arteriovenous fistula was created to improve oxygenation, but its effectiveness was compromised by the pulmonary fistulas. Transcatheter coil embolization of the pulmonary fistulas was performed with clinical improvement.

Adolescent↗
PubMed1983

From cyanotic infant to acyanotic adult - the odyssey of blue babies.

An edited summary of an Interdepartmental Conference arranged by the Department of Medicine of the UCLA School of Medicine, Los Angeles. Director of Conferences: William M. Pardridge, MD, Associate Professor of Medicine.In the past two decades we have witnessed the maturing of diagnostic and surgical skills in the management of congenital heart disease. Although longevity and quality of life have improved, cures are few; varying degrees of postoperative medical supervision are therefore needed. This new patient population of adults requiring long-term medical care continues to increase. Proper management of such patients can be taxing, requiring knowledge not only of the preoperative disease but also of the nature and effects of surgical intervention and of the presence, type and extent of late postoperative residua and sequelae. The tetralogy of Fallot is taken as a model because it is well known in both pediatric and adult medicine, because intracardiac repair includes a wide range of techniques and because postoperative residua and sequelae comprise a broad spectrum of patient care concerns.

Adult↗
PubMed1983

Warm induction of cardioplegia with glutamate-enriched blood in coronary patients with cardiogenic shock who are dependent on inotropic drugs and intra-aortic balloon support.

This report reviews the initial clinical application of our experimental studies inducing cardioplegia with a warm (37 degrees C) glutamate-enriched blood solution in ischemically damaged hearts. Over 15 months, 23 consecutive coronary patients requiring preoperative intra-aortic balloon and inotropic drug support for cardiogenic shock underwent operation for left ventricular power failure. Twelve patients were given a warm glutamate-enriched blood cardioplegic solution during the first 5 minutes of aortic clamping before multidose cold (4 degrees C) glutamate blood cardioplegia was begun; 11 patients received standard multidose cold blood cardioplegia without glutamate. All patients had comparably depressed left ventricular performance preoperatively despite maximal inotropic and balloon support and showed evidence of extending myocardial infarction. They did not differ in the number of grafts placed (3.7 +/- 0.2), associated valve and aneurysm procedures (seven patients) or cross-clamp time (89 +/- 6 minutes). All patients received warm blood cardioplegic reperfusion before aortic unclamping. The perioperative mortality was 9% (2/23); both patients who died received cold blood cardioplegia without glutamate. In addition to lower mortality, patients receiving warm glutamate blood cardioplegia exhibited better hemodynamics, allowing earlier discontinuation of inotropic drug infusion (1.3 +/- 0.5 versus 2.7 +/- 0.8 days, p less than 0.05) and intraaortic balloon support (1.2 +/- 0.2 versus 3.6 +/- 0.5 days, p less than 0.05). Late mortality was 30%, resulting in a 65% overall survival rate (2 to 15 months) for the entire series of patients. The operative principles evolving from this early experience include (1) warm blood cardioplegic induction, (2) glutamate enrichment, (3) meticulous attention to cardioplegic distribution and grafting sequence, (4) warm cardioplegic reperfusion before unclamping, and (5) graft perfusion during construction of proximal anastomoses. Hopefully, further application of these techniques will improve results in these extremely high risk coronary patients requiring operation.

Aged↗
PubMed1982

Continuous monitoring of left ventricular performance with the computerized nuclear probe during laryngoscopy and intubation before coronary artery bypass surgery.

Left ventricular performance was monitored serially in 25 patients during laryngoscopy and intubation in the anesthetic induction period before elective coronary artery bypass surgery using the labeled equilibrium blood pool and the computerized nuclear probe. Left ventricular ejection fraction was obtained preoperatively, after induction of anesthesia but before endotracheal intubation, immediately after intubation, and at 1 minute intervals thereafter for 10 minutes. In all patients, there was an immediate decrease (mean 16%) in left ventricular ejection fraction accompanying the reflex hypertension and tachycardia occurring during laryngoscopy and endotracheal intubation; it was significantly depressed for 3 minutes with the concomitant hemodynamic changes. Seven patients did not demonstrate a recovery of left ventricular ejection fraction to the preintubation value. In 10 healthy noncardiac patients undergoing orthopedic surgery, after an identical anesthetic induction sequence and intubation, there was a similar decrease in ejection fraction, but of shorter duration. In these patients the recovery of left ventricular performance preceded the recovery of blood pressure and heart rate. This study demonstrates that profound decreases in left ventricular performance accompany the reflex hypertension and tachycardia occurring during endotracheal intubation and that there is persisting depression of left ventricular function in some patients with coronary artery disease. These findings indicate the potential utility of the computerized nuclear probe for monitoring ventricular performance during this critical period.

Adult↗
PubMed1982

Changing patterns in the surgical management of ventricular septal rupture after myocardial infarction.

Seventeen consecutive patients who underwent repair of postinfarction ventricular septal rupture between 1975 and 1980 at the Yale-New Haven Medical Center are reported on. The most important prognostic indicator of a favorable outcome was the patient's preoperative hemodynamic state. The mortality rate ranged from 83 percent for patients in shock to no mortality in patients with mild to moderate symptoms. There was a strong tendency for hemodynamic deterioration despite hemodynamic support with pharmacologic agents as well as intraaortic balloon pumping. Our review indicates that several patients might have been saved if operation had been performed earlier. Based on this experience and that of others, a management plan is formulated, and we recommend early surgical intervention in all operable patients with ventricular septal rupture. In patients with severe cardiogenic shock, we forego full cardiac catheterization, confirming the diagnosis by an oxygen step-up in the pulmonary artery only. These patients undergo operation on an urgent basis. No undue technical difficulties were related to early operation. At present, maximum survival of patients with postinfarction ventricular septal rupture may be accomplished by early surgical intervention in all operable cases.

Aged↗
PubMed1982

Radionuclide assessment of left ventricular function in patients requiring intraoperative balloon pump assistance.

Twenty-three surviving patients who were weaned from cardiopulmonary bypass with intraaortic balloon pump assistance returned for follow-up radionuclide left ventricular (LV) function and thallium 201 perfusion studies at a mean of 23 +/- 3 months following operation. It was found tat despite profound intraoperative myocardial depression requiring intraaortic balloon assistance, 13 patients had no change (within 10%) in the resting LV ejection fraction compared with the preoperative measurement. Among all 23 patients, there was no difference between mean (+/- standard error of the mean) preoperative and postoperative resting LV ejection fraction (48 +/- 4 vs 46 +/- 4%, p = not significant [NS]). Only 11 patients had perioperative myocardial infarction documented by new Q waves in the electrocardiogram, by elevation of creatine kinase-MB fraction, or by defects on thallium 201 imaging not explained by documented myocardial infarction before operation. Overall, postoperative resting LV ejection fraction was not different from the preoperative value in patients with perioperative myocardial infarction (44 +/- 7 vs 47 +/- 5%, p = NS). Postoperative resting LV ejection fraction rose by greater than 10% compared with preoperative values in 4 patients (3 with aortic valve replacement), remained within the 10% limit in 9 patients, and fell by greater than 10% in 10 patients (7 with perioperative myocardial infarction). Only 4 out of 16 patients studied at follow-up with exercise radionuclide studies demonstrated a normal LV response to exercise (greater than 5% increase in LV ejection fraction). Thus, among survivors requiring intraaortic balloon pump assistance for weaning from cardiopulmonary bypass, LV performance at rest is frequently preserved. In addition, 11 of the 23 patients had evidence of perioperative myocardial infarction, indicating a component of reversible intraoperative LV dysfunction.

Adult↗
PubMed1982

Factors affecting performance and thromboembolism after porcine xenograft cardiac valve replacement.

Long-term durability and the need for anticoagulation in conjunction with the use of porcine valves remain questionable. We analyzed valve dysfunction and thromboembolism in 325 adult (older than 20 years) and 31 pediatric survivors who received 407 porcine xenograft valves from June, 1974, to September, 1980 (46% of all valve replacements). Valves at risk in the adults were 216 aortic, 138 mitral, and 22 tricuspid; in children, 14 aortic, eight mitral, seven pulmonary, and two tricuspid. Mean follow-up was 38 (9 to 85) months. Twenty-seven valved conduits also were followed up for 9 to 85 (mean 52) months. Two late deaths in children resulted from dysfunction and another from endocarditis. One late death in an adult was caused by embolism. The other 36 deaths in the entire group were not valve related. Dysfunction requiring reoperation at 12 to 37 months occurred in eight of 325 adults (six mitral, one aortic, and one tricuspid). Dysfunction was due to recurrent endocarditis in six and to primary tissue failure in two (both older than 35 years of age); all survived reoperation. However, in children, severe dysfunction due to primary tissue failure occurred in seven (23%) cardiac valves, necessitating replacement at 21 to 48 months, and three of 27 conduits had to be replaced at 39 to 70 months. Thromboembolism occurred in six adults with mitral xenografts but none with aortic or tricuspid valve. Four of the patients with thromboemboli (one of whom died) were among 16 who had atrial fibrillation and no warfarin, but aspirin and persantine (11.7%/patient-year) and two were among 14 with sinus rhythm on no medication. No thromboembolism occurred in patients with mitral xenografts who were in sinus rhythm and receiving antiplatelet agents or in those with atrial fibrillation receiving warfarin. This experience indicates a high incidence of relatively early failure of porcine xenograft cardiac valves in children and young adults but excellent medium and long-term performance in older adults, in whom severe dysfunction occurred mainly with recurrent endocarditis. Thromboembolism occurred primarily in patients with mitral replacement especially with atrial fibrillation and no anticoagulants.

Adult↗
PubMed1982

Reversible changes in norepinephrine extraction by the lungs in children with pulmonary hypertension.

Extraction of circulating vasoactive hormones by the lung may influence systemic vasomotor tone. Since this process occurs in the pulmonary microcirculation, we evaluated the effects of pulmonary artery hypertension (PAH) secondary to congenital heart disease (CHD) on this metabolic function of lung. Eleven patients with varying congenital cardiac lesions were studied preoperatively and postoperatively. Five had normal pulmonary artery pressure (PAP) (group I), and six had PAH with peak systolic PAP greater than 40 mm Hg (group II). PA and postpulmonary arterial blood samples were collected before and after surgery at the time of pressure measurements. Norepinephrine (NE) and epinephrine (EPI) levels were determined by radioenzymatic assay. Preoperatively, circulating NE levels were higher (P less than 0.05) and NE extraction measured was lower (P less than 0.01) in group II patients as compared with group I. Extraction increased in group II postoperatively after PA pressures were reduced, becoming equivalent to group I postoperative values. EPI extraction was negligible in either group at any time. These data demonstrate that lungs of children are capable of selective catecholamine uptake and that elevated PAP occuring with CHD is associated with a decrease in this capability and an increase in circulating NE levels. Additionally, the decrease in NE extraction observed with PAH is reversible once PAP is reduced by surgical repair of the cardiac defect.

Adolescent↗
PubMed1982

Use of cold blood cardioplegia to protect against coronary microcirculatory injury due to ischemia and reperfusion.

The effect of cold blood cardioplegia in preventing microvascular injury owing to myocardial ischemia and reperfusion was studied. Two groups of eight dogs each were placed on cardiopulmonary bypass with separate coronary perfusion at 80 mm Hg. Microcirculatory function was assessed by measuring the extraction and permeability surface area product (PS) for inulin and albumin. These changes were correlated with the transport and extraction of oxygen, coronary blood flow, and morphologic studies of the microvasculature. In Group I, ischemic hearts were kept normothermic for 45 minutes. In Group II, 250 ml of cold (4 degrees C) blood cardioplegic solution (potassium chloride 30 mEq/L) was infused and the infusion repeated at 15 and 30 minutes. Reperfusion resulted in marked reactive hyperemia for Group I (p less than 0.05) but no hyperemic response in Group II. In Group I, but not II, ischemia-reperfusion caused a significant decrease in PS inulin (0.47 +/- 0.10 ml/min/gm) compared to the preischemic value (1.04 +/- 0.23) (p less than 0.05). There was a threefold decrease in the PS inulin/PS albumin ratio with reperfusion in Group I, indicating increased vascular permeability to albumin. There was also a significant decrease in myocardial oxygen consumption (from 5.1 +/- 0.7 to 3.4 +/- 0.5 ml/min/100 gm, p less than 0.05) for Group I. These did not decrease for Group II. Histologic studies showed diffused areas of no reflow in the unprotected hearts. The wet/dry weight ratio for Group I (4.97 +/- 0.09) was significantly greater than for Group II (4.49 +/- 0.07) (p less than 0.001). The results indicate that in the unprotected heart, ischemia-reperfusion caused microcirculatory injury resulting in increased permeability to albumin, edema, a reduction in surface area, and areas of no reflow. In contrast, in the hearts protected with cold blood cardioplegia, no evidence of microcirculatory injury occurred.

Albumins↗
PubMed1981

Use of silicone rubber to facilitate shunt takedown.

The takedown of systemic-pulmonary artery shunts at the time of corrective operation is time-consuming and potentially dangerous because of adhesions at the previous operative site. A method of facilitating shunt takedown is described in which a strip of silicone rubber is used to surround the subclavian artery or polytetrafluoroethylene graft interposed between the subclavian artery and the pulmonary artery. The ends of the strip are left loosely attached to the anterior mediastinum so that an adhesion-free plane is left between the strips down to the shunt. The experience of the Yale University School of Medicine with this technique in 14 patients is described. Five underwent reoperation, at which time the silicone rubber strip facilitated access to the shunt and shunt takedown.

Blood Vessel Prosthesis↗
PubMed1981

Catheter-induced pulmonary artery perforation. Mechanisms, management, and modifications.

Six cases of pulmonary artery perforation associated with the use of Swan-Ganz catheters are reviewed. Risk factors included pulmonary hypertension, anticoagulation, and hypothermia. The mechanisms leading to perforation were clarified by the use of postmortem studies employing isolated whole lung preparations. These studies revealed that perforation results from (1) tip perforation of vasculature, (2) eccentric balloon configuration propelling the balloon through the vessel wall, and (3) balloon inflation disrupting the pulmonary artery (mean intraballoon pressure 250 mm Hg). Early clinical symptoms include hemoptysis of bright red blood and/or hypotension. Immediate evaluation may necessitate examination with a fiberoptic bronchoscope and "wedge" angiogram. If massive hemoptysis occurs, isolation of the unaffected lung by endobronchial intubation is mandatory. Pneumonectomy or lobectomy may be required. Revised guidelines for catheter insertion and pulmonary capillary wedge pressure (PCWP) measurements are presented. Finally, consideration is given to redesigning the pulmonary artery flow-guided catheter, particularly for use in patients undergoing cardiac operations with systemic anticoagulation. Modifications should be directed at (1) softer catheter tip with temperature-insensitive body, (2) low-pressure balloon, and (3) balloon pressure relief valve.

Aged↗
PubMed1981

Use of silicone rubber as a pericardial substitute to facilitate reoperation in cardiac surgery.

Reoperations following cardiac procedures have an increased risk because of the danger of damaging the heart, great vessels, or grafts because of adhesions to the sternum and anterior chest wall. We report our experience with the use of silicone rubber as a pericardial substitute in 102 patients--58 children undergoing palliative and corrective operations and 44 adults undergoing porcine valve insertion or coronary revascularization. The pericardial substitute was used only in cases in which reoperation was considered likely. There were no mediastinal infections. One adult had signs of cardiac constriction which improved markedly on administration of anti-inflammatory agents. Seven patients required reoperation for bleeding. Two patients who underwent Fontan procedures developed pericardial effusions necessitating a pericardial window. Reoperation was undertaken 1 to 12 months postoperatively in seven patients, all of whom were children. The silicon rubber greatly facilitated opening of the chest bone but did not affect the formation of adhesions within the pericardium. Postmortem examinations have been obtained in two cases 5 and 9 months postoperatively, and showed a thin layer of dense fibrous tissue adjacent to the silicone rubber. We conclude that silicone rubber may be used as a pericardial substitute and that it facilitates reoperation following cardiac operations. Particular caution should be used in patients undergoing Fontan procedures, as there appears to be a tendency for pericardial effusions and tamponade to develop.

Adult↗