Atrial defibrillation using temporary epicardial defibrillation stainless steel wire electrodes: studies in the canine sterile pericarditis model.

OBJECTIVES: This study sought to determine whether temporary epicardial wire electrodes can be used safely and effectively to defibrillate the atria with low energy shocks in the absence of anesthesia. BACKGROUND: Atrial fibrillation after open heart surgery is a significant clinical problem. METHODS: Twelve dogs with sterile pericarditis were studied. In the first group (6 dogs, bilateral thoracotomy group), a wire electrode, insulated except for the distal 6 cm, was placed on the epicardial free wall of each atrium. Each end of the bare wire was then sutured to the parietal pericardium. In the second group (6 dogs, median sternotomy group), the wire electrodes were kept in place by a double loop of Prolene placed around the distal tip of the bare wire and sewn to the overlying parietal pericardium. In the bilateral thoracotomy group, atrial defibrillation thresholds (defined as < 90% and > 10% successful defibrillation of 20 shocks at a given delivered energy) were obtained in anesthetized dogs using the wire electrodes with the chest closed and open and using two transvenously placed catheters with coil electrodes in the distal 6 cm (one in the coronary sinus and the other in the right atrial appendage) with the chest open. In the median sternotomy group, thresholds were obtained in minimally sedated animals without reopening the chest. A 25% increase above threshold shock was also used to determine a new percent success. After 4 days, the wire electrodes were removed by pulling on the external ends. At the time of removal, blood pressure and heart rate were monitored for 30 min, after which dogs were killed and their hearts sent for histopathologic study. For all dogs, chest radiographs were obtained postoperatively and on study days. RESULTS: Atrial defibrillation using the wire electrodes was successful in all dogs at a mean (+/- SE) voltage of 112 +/- 9 V, with an energy level of 0.46 +/- 0.07 J and an impedance of 59.3 +/- 5 ohms. The mean percent success at the atrial defibrillation threshold was 36 +/- 5%. The 25% increase in defibrillation voltage improved the mean percent success to 73% (mean energy 0.66 +/- 0.19 J). No clinical or hemodynamic complications were observed during shock delivery, and no ventricular arrhythmias were induced during the shocks. No complications followed wire electrode removal. Histopathologic analysis showed no structural damage. CONCLUSIONS: The atrial defibrillation threshold obtained using temporary epicardial wire electrodes for atrial defibrillation is < 1 J in dogs. Atrial defibrillation using temporary epicardial wire electrodes can be performed safely, quickly and reliably without the need for anesthesia or antiarrhythmic agents. The wire electrodes can be removed without adverse hemodynamic or structural consequences. These data provide a basis for testing atrial defibrillation using epicardial wire electrodes in patients after open heart surgery.

Cardiac function, coronary flow and MVO2 in hypertrophy induced by pressure and volume overloading.

Myocardial function, flow and O2 consumption were compared in cardiac hypertrophy induced by pressure-loading (P) and by volume overloading (V). Increases in LV-to-body weight ratios in P and V hypertrophied hearts were comparable. Indices of LV function such as cardiac output, stroke volume, stroke work, minute work, peak LV dP/dt, ratio of peak LV dP/dt-to-isovolumic pressure and -to-LVEDP, and Vmax were significantly reduced from normal only in hypertrophy induced by V. Left ventricular coronary flow was reduced from 167.1 +/- 27.2 in normal dogs to 146.2 +/- 17.1 cm3/min-100 g-1 in P hypertrophy, and was reduced further to 82.5 +/- 8.2 cm3/min-100 g-1 in V hypertrophy. Flows decreased similarly in epicardium and endocardium in both hypertrophied hearts. Cardiac O2 extraction in P and V hearts was greater than in control hearts. Myocardial O2 consumption was maintained at control values in P hypertrophy, and decreased by 54 +/- 3% in V hypertrophy. These findings indicate that LV function is impaired at rest in hypertrophy induced by V and is normal in hypertrophy induced by P.

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.

Modification of intraaortic balloon catheter to permit introduction by cardiac catheterization techniques.

Intraaortic balloon counterpulsation has been widely applied for treatment of left ventricular pump failure and intractable angina. However, its use has been limited by the difficulty of balloon insertion in some patients and vascular complications in others. An AVCO intraaortic balloon was modified by the addition of a central lumen to allow pressure monitoring, injection of contrast medium and passage of a guide wire. The device was successfully used in 15 of 16 patients, including 4 of 5 in whom attempts to place a standard balloon catheter had failed. No significant vascular complications occurred in any patient. The modified balloon catheter appears to increase the efficacy and safety of insertion and allows immediate and continuous monitoring of arterial pressure.

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.

Hemodynamic response to pumpless extracorporeal membrane oxygenation.

Respiratory support by means of arteriovenous extracorporeal membrane oxygenation driven by systemic arterial pressure, in contrast to pump-driven venoarterial extracorporeal membrane oxygenation, is attractive because of its simplicity and lack of trauma to formed blood elements. Although arteriovenous extracorporeal membrane oxygenation has been shown to improve arterial blood gases, useful levels of arteriovenous extracorporeal membrane oxygenation shunt flow may exert detrimental effects on systemic and pulmonary hemodynamics. Therefore the hemodynamic consequences of arteriovenous extracorporeal membrane oxygenation were studied in 11 dogs that were anesthetized, heparinized, and their lungs mechanically ventilated (FIO2 = 0.21) before and after induction of oleic acid pulmonary edema. The data indicate that arteriovenous extracorporeal membrane oxygenation shunt flows adequate to improve arterial blood gases resulted in significant changes in peripheral vascular resistance (-46%; p less than 0.05), systemic arterial blood pressure (-20%; p less than 0.05), and cardiac output (+110%; p less than 0.05). Dopamine infusion (5 micrograms/kg/min) proved to be more effective than volume expansion (15 ml/kg) in maintaining cardiac output, arterial blood pressure, and arterial blood gases. We conclude that pumpless arteriovenous extracorporeal membrane oxygenation, at flow rates adequate for respiratory support, can adversely alter systemic hemodynamics. However, these effects can be beneficially modulated by a moderate dose of inotropic medication.

Successful emergency replacement of the ascending aorta and aortic and mitral valves in the Marfan syndrome.

A 37-year-old man with the Marfan syndrome and chronic mitral regurgitation suffered an acute dissecting aneurysm of the ascending aorta with aortic regurgitation. Emergency replacement of the mitral valve, aortic valve, and ascending aorta was carried out, and the patient made an uneventful recovery. He is doing well 18 months after surgery. This is the first reported case of survival from such a procedure in the face of acute dissection with Marfan's syndrome. Indications for elective surgery are discussed and the uncertainties about the prognosis outlined. Continued reporting of the results and follow-up data are necessary for final assessment of the surgical treatment of the cardiovascular manifestations of this disease.

Severe coarctation of the aorta with pulmonary edema. An unusual presentation of a traumatic aortic aneurysm.

A patient with an unrecognized rupture of the ascending aorta developed severe pulmonary edema three weeks following the initial injury. This is a distinctly unusual manifestation of this injury. Emergency resection of the traumatic aneurysm was required to reverse the rapidly deteriorating clinical situation. The early recognition and surgical treatment of this lesion would have avoided this complication.

Selection of coronary bypass. Anatomic, physiological, and angiographic considerations of vein and mammary artery grafts.

Results of direct coronary revascularization with 511 grafts in 213 patients from 1971 to 1974 are reviewed. To improve an early saphenous vein graft (SVG) patency of 84 per cent in the first 85 patients, we have used internal mammary artery grafts (IMAG), when possible, since January, 1973. In 1973 to 1974, 15 patients had SVG's only (36 grafts) and 113 received one or two IMAG's with or without additional SVG's (total 282 grafts); in 26 we used a crossed double IMAG. Forty-seven of 48 patients with unstable angina survived and did well. Flows in SVG's and IMAG's were comparable. Flows in right IMAG's to diagonal or marginal vessels were higher than in right IMAG's to right or left anterior descending (LAD) vessels. In 12 patients with both SVG and IMAG, there was no difference in flow response of either graft to vasoactive drugs. Survival, functional, and patency results with IMAG's were as good as or better than results with SVG's. We conclude that IMAG's yield higher patency and comparable flow rates to SVG's and should be used when the IMA approximates the recipient artery in size and when a high pulsatile free flow is measured from the end of the graft. IMAG's are also safe and feasible for unstable angina.

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.

Randomized comparison of the modified wire-guided and standard intra-aortic balloon catheters.

We have designed a modified intra-aortic balloon (IAB) catheter to facilitate balloon insertion and minimize the complications of vascular dissection, perforation, and thrombosis. The modified balloon catheter is fabricated of a new polyurethane, Avcomat-100; it has a central lumen which allows for pressure monitoring, contrast injection, and introduction of a guide-wire under fluoroscopic control. In a randomized study, we compared the modified balloon with the standard Avco balloon catheter. Eighteen patients were randomized, 10 to receive a standard balloon catheter (control group) and eight to receive a modified balloon catheter. In two of the 10 patients assigned to the control group, introduction of the standard catheter failed but a central-lumen balloon was successfully introduced using the guide wire. A guide wire was needed for introduction of the modified balloon in three of the eight patients assigned to the central-lumen catheter group. The Avcomat-100 catheter material was less thrombogenic, with a lower rate of femoral thrombosis--20% in the control group and 0% in the central-lumen group. Scanning electron miroscopy also showed a reduced area of catheter surface covered with fibrin and clot. This study demonstrates the safety, decreased thrombogenicity, and increased facility of insertion of this new balloon catheter.

Biological versus mechanical valves. Analysis of 1,116 valves inserted in 1,012 adult patients with a 4,818 patient-year and a 5,327 valve-year follow-up.

All surviving patients between 18 and 88 years of age receiving biological or mechanical prosthetic heart valves at the Yale-New Haven Hospital from January 1974 through January 1985 were analyzed for thromboembolism, anticoagulation-related hemorrhage, endocarditis, perivalvular leak, valve failure, need for reoperation, late cardiac death, and valve-related death. The rates of these events were analyzed in linear and actuarial terms over the 11 year period. A total of 533 patients received 606 biological valves (328 aortic, 252 mitral, 24 tricuspid, and two pulmonary, consisting of 482 Carpentier-Edwards, 108 Hancock, 15 Ionescu-Shiley, and one other), with a mean follow-up of 2,571 patient-years and 2,935 valve-years. They were compared with 479 patients with 510 mechanical valves (330 aortic, 175 mitral, and five tricuspid, consisting of 178 Starr-Edwards, 166 St. Jude Medical, 164 Björk-Shiley, and two others), which were implanted for 2,247 patient-years and 2,392 valve-years. We found a significantly increased incidence of thromboembolism (p less than 0.001) and reoperation for perivalvular leak (p less than 0.05) in the mechanical valves compared with the biological valves, but a significantly increased rate of valve failure (p less than 0.001) in the biological valves compared with the mechanical valves. The overall analysis comparing total morbidity and valve-related mortality significantly (p less than 0.01) favored the biological valves in the first 5 years of the study and the mechanical valves (p less than 0.001) in the second 5 years of the study. However, the net 10 year results showed no significant difference between the two types of valves. In summary, we found little direct evidence to strongly support the generalized use of one type of valve over another.

Surgical treatment of unstable angina by saphenous vein and internal mammary artery bypass grafting.

During a 3 year period, direct myocardial revascularization was performed on an urgent basis in 48 patients with intermittent resting chest pain which persisted more than 24 hours despite in-hospital medical therapy and was accompanied by electrocardiographic changes representative of ischemia. Sixteen patients had saphenous vein (SV) grafts exclusively, and 32 patients each had one or two internal mammary artery (IMA) grafts with or without additional vein grafts. Follow-up ranges from 5 to 41 months (mean, 22 months). Twelve patients had single grafts to the left anterior descending coronary artery (LAD), 18 had double grafts, 16 had triple grafts, and 2 had quadruple grafts. The LAD required grafting in every patient. There was one operative death (2 per cent) and one late death from noncardiac causes. There were two (4 per cent) early postoperative myocardial infarcts and no late infarcts. Actuarial analysis projects a survival rate of 96 per cent 3 years postoperatively. Eighty-one per cent of the survivors are in Functional Class I, 17 per cent are in Class II, and 2 per cent are in Class III. All patients had postoperative angiography 2 weeks after operation. Eighty-six per cent of the SV grafts and all IMA grafts were open. No significant differences were observed between mean preoperative and postoperative left ventricular end-diastolic pressures or ejection fractions, but these parameters were noted to improve after operation in several patients. The remarkably high early and late survival rates, the low incidence of myocardial infarction, and the excellent functional results after rather long follow-up indicate that emergency coronary revascularization provides an effective therapy for unstable angina. The use of IMA grafts, when feasible, is a safe and possibly preferable approach in these patients.

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.

Late failure of porcine valve heterografts in children.

Heterograft porcine valves have gained wide acceptance in replacement of diseased cardiac valves, and their clinical performance in adults has been very satisfactory over follow-up periods of up to 8 years. Valve replacement in children is relatively infrequent and experience with porcine xenografts is necessarily small. Our combined experience at three university hospitals has been with 25 children, 17 months to 16 years of age, who have been followed for 10 to 54 months (mean follow-up 33 months). Porcine valves were used to replace the aortic valve in nine, the mitral valve in seven, both valves in two, the tricuspid valve in two, and the pulmonary valve in five patients. Severe bioprosthetic valve dysfunction has occurred in five (20%) of these patients so far and necessitated replacement because of severe stenosis in mitral (two) or aortic (three) valve prostheses at 18 to 45 months after implantation; one postoperative death occurred among the five reoperations. Pathological examination showed extensive fragmentation of collagen with focal heavy calcification and degeneration. In addition we have encountered deterioration and calcification of two porcine valves in 23 valved conduits followed for 12 to 70 months (mean 43 months), requiring removal and replacement of the valves 65 and 67 months after implantation. This experience indicates a disquietingly high incidence of relatively early failure of porcine xenograft valves in children. This is significantly higher than the failure rate observed in adult patients. The failure rate is not consistently related to the small size of an implanted valve which becomes relatively narrow with the growth of the patient, leading to excessive turbulence and trauma to the prosthesis. Other factors, including increased turnover of calcium and accelerated rejection in growing children, may contribute to these failures and should be examined in order to improve long-term results. A satisfactory performance would make heterografts the ideal valvular prosthesis in children, since anticoagulation is avoided.

Successful atrial defibrillation with very-low-energy shocks by means of temporary epicardial wire electrodes.

Sustained atrial fibrillation is very common after cardiac surgical procedures. We hypothesized that atrial defibrillation could be accomplished consistently and safely by means of low-energy shocks delivered by temporary stainless steel wire electrodes placed at the time of the operation. Sterile pericarditis was created in five mongrel dogs (20.9 +/- 2.1 kg), and pairs of standard temporary stainless steel wire electrodes were placed on the right atrial appendage, on Bachmann's bundle, and on the right ventricular apex for pacing, sensing, and recording. Temporary stainless steel wire electrodes, insulated except for the distal 6 cm and used to deliver defibrillation shocks, were placed adjacent to both atrial free walls and secured to the pericardium. All electrodes were brought out through the skin, and the sternotomy was closed. Dogs were tested in the conscious state on postoperative day 2. Sustained atrial fibrillation was induced by rapid atrial pacing. A customized software program was used to control the defibrillator, which delivered R wave-synchronous biphasic shocks to the atria through the temporary defibrillation electrodes. The shock intensity began at 50 volts and was increased by 10-volt increments until atrial fibrillation was terminated. Atrial fibrillation was terminated in all dogs at 112 +/- 7 volts, with an energy of 0.42 +/- 0.07 joule and an impedance of 67.8 +/- 4 ohms (all values mean +/- standard error of the mean). The mean percent success for atrial defibrillation at this minimal threshold was 49%. Thus at low-threshold voltages atrial fibrillation could be terminated with every other shock. A 25% increase in the minimal threshold voltage improved the conversion rate to 73% (mean energy 0.66 +/- 0.19 joule and mean impedance of 67 +/- 3.8 ohms). No complications were detected with the use of the electrodes or after their removal on the seventh postoperative day. One instance of electrode migration on the right atrial free wall was detected by roentgenography, but this did not adversely affect atrial defibrillation threshold. No ventricular arrhythmias or hemodynamic complications were noted during shock delivery. We conclude that successful conversion of atrial fibrillation to sinus rhythm can be achieved consistently with shock energies below 0.5 joule delivered with temporary epicardial defibrillation wire electrodes in this canine pericarditis model. These results suggest that this approach to the management of sustained atrial tachyarrhythmias has considerable promise in the management of atrial fibrillation in patients who have had cardiac operations.

Coronary and cardiovascular dynamics and oxygen availability during acute normovolemic anemia.

The hematocrit of 12 dogs was reduced from 43 to 30 and then to 20% by bleeding and simultaneous infusion of lactated Ringer's solution. At each level of anemia, blood volume, heart rate, cardiac output, left and right pressures, left ventricular (LV) work, aortic mean pressure, and systemic vascular resistance were at prebleeding values. Pulmonary arterial saturation decreased from 76 to 67 and 50%. LV coronary venous saturation fell from 46 to 31% at hematocrit 30, with no further reduction at hematocrit 20. Electromagnetically measured left coronary mean flow was 120 and 185% of control at hematocrits 30 and 20. Coronary flow reserve, or the ratio of peak increase in flow after 10 second occlusion to preocclusion flow, was 3.8 at hematocrit 43, 3.0 at 30, and 1.9 at 20. The change in ratio was due to increased resting flow with anemia, whereas peak reactive hyperemia flow did not change with hematocrit. Acute normovolemic anemia is not associated with significant changes in cardiac work. Despite lowered blood viscosity, systemic resistance is maintained by vasoconstriction. Systemic oxygen availability (Cardiac output X arterial O2 content) is decreased, but uptake is maintained by increased O2 extraction. LV O2 consumption is maintained by maximally increasing the already high myocardial O2 extraction and by increasing coronary flow. At half-normal hematocrit, coronary reserve is compromised significantly, indicating cardiac vulnerability at these levels of anemia, especially if coronary occlusive disease or higher work demands on the heart should coexist.

Evolution of the surgical approach for replacement of degenerated mitral bioprostheses.

BACKGROUND: Primary tissue failure is the most frequent indication for reoperation in patients with a mitral bioprosthetic valve (MBPV). Complete excision of the bioprosthesis is time-consuming and may be complicated by cardiac rupture at the atrioventricular junction or the posterior left ventricular wall where a strut is embedded, injury to the circumflex coronary artery, or late perivalvular leak. A new approach to avoid these complications by excision of only the bioprosthetic tissue and attachment of a St. Jude valve (SJV) to the intact stent has been developed and evaluated. METHODS: The results of replacement of failed MBPV with SJV in 71 consecutive patients between September 1992 and December 1994 were analyzed; 57 patients had the valve replaced after complete excision and 14 with stent preservation. The demographic and clinical profiles of the two groups were similar. RESULTS: Among patients undergoing complete excision of the MBPV, operative mortality was 14% (8 of 57), with 12 late deaths and a 5-year survival of 75% and three late perivalvular dehiscences requiring another operation. No operative deaths occurred in the intact stent group and one late death (cancer), and all the remaining patients are doing well without perivalvular leaks or other complications. CONCLUSIONS: Leaving the MBPV stent intact eliminates the need for extensive dissection, thus shortening and simplifying the procedure and diminishing its attendant mortality and morbidity. It offers a safe and logical approach to replacement of a degenerated MBPV with a SJV of comparable size.

A 32-year experience in 100 patients with giant paraesophageal hernia: the case for abdominal approach and selective antireflux repair.

BACKGROUND: Giant paraesophageal hiatal hernia (GPEH) presents a risk of catastrophic complications that include massive bleeding, strangulation, and perforation and should be repaired. Controversy persists as to the surgical approach and whether an antireflux repair is required. METHODS: This study reviews the experience with 100 patients with GPEH who underwent surgical repair between 1967 and 1999. Eighty patients underwent an elective operation, and 20 patients underwent an emergency procedure for complications of GPEH. The gastroesophageal junction was above the hiatus ("combined" hernia with sliding component) in 23 patients and in the abdomen in 77 patients, including 3 patients with a true parahiatal hernia. RESULTS: A thoracic approach was used in 18 patients, mostly early in our experience; postoperative gastric volvulus requiring transabdominal repair developed in 2 patients. The remaining 82 patients underwent an abdominal repair, with temporary gastrostomy to prevent gastric displacement in 75 patients; the hernial sac was resected, and the hiatus was reconstructed in all of the patients. Thirty-five patients with reflux on preoperative work up underwent a fundoplication, with gastroplasty in 2 patients because of a short esophagus. No patient has experienced hernia recurrence. Whereas symptomatic relief was excellent in all patients with elective repair, mild reflux was present in 2 patients after emergency operation. There were no deaths among the patients who underwent elective operation; there were 2 hospital deaths among those patients who underwent emergency operation (10%). CONCLUSIONS: GPEH should be repaired soon after recognition. Reflux should be evaluated before the operation, and if present, fundoplication should be part of the repair along with the reduction of the hernia, excision of the sac, gastropexy, and crural closure. These are best achieved with an abdominal approach.

Long-term outcome of revascularization of the anterior coronary arteries with crossed double internal mammary versus saphenous vein grafts.

When simultaneous revascularization of the left anterior descending (LAD) artery and the proximal segments of the diagonal LAD and marginal coronary arteries is required, the direction and location of these vessels allow excellent alignment of the left internal mammary artery (IMA) with the LAD and the right IMA with the diagonal LAD or marginal arteries, an approach originally described in 1976. To analyze and compare the long-term outcome of this approach versus the saphenous vein bypass graft (SVG) approach for anterior coronary revascularization, we reviewed 43 patients who had these crossed double IMAs (CDIMAs) and 53 patients who had SVGs to the same obstructed anterior coronary arteries during 1973 to 1978; 32 patients in the CDIMA group and 43 in the SVG group also had SVGs to other diseased vessels. The two groups had similar demographic and epidemiologic characteristics. The linearized incidence of late cardiac death, reoperation, recurrent angina, and infarction was 0.2%, 0.7%, 1.4%, and 0% per patient-year, respectively, in the CDIMA group, and 1.6%, 2.4%, 7.8%, and 1.8% per patient-year in the SVG group (p less than 0.01 for each event). At 5 years, the actuarial number of patients with CDIMAs free of late cardiac death was 100%, of reoperation 98%, of recurrent angina 98% (p less than 0.01), and infarction 100% (p less than 0.01), versus 94%, 98%, 84%, and 94%, respectively, in the SVG group. At 10 years, the actuarial incidence of all events was substantially and significantly less in patients with CDIMAs. CDIMAs have significantly better prognostic effects than SVGs when revascularization of the anterior coronary arteries is required. This is currently our preferred approach in these selected patients.