Telemedicine infrastructure development

While there are significant technical and regulatory barriers to developing an adequate infrastructure for telemedicine, even more fundamental organizational and financial infrastructure issues must be addressed if this technology is to realize its potential. The lack of good evaluative data on telemedicine consultations has been a further major stumbling block to its acceptance by both practitioners and policy-makers. This paper discusses these issues and suggests approaches for overcoming many of the impediments to telemedicine.

Oblique transseptal left atriotomy for optimal mitral exposure

Twenty patients underwent mitral valve replacement or other surgical procedures within the left atrium with Dubost's transseptal left atriotomy. The left atrium was grossly enlarged in six patients. Exposure was considered to be excellent in 13 patients and poor in only two. One patient (with a second aortic and mitral valve replacement) required a permanent pacemaker after operation, none had a residual shunt at the atrial level, and none required reoperation for bleeding. The Dubost transseptal left atriotomy affords excellent exposure of left atrial structures, is easy to close, and does not increase the prevalence of postoperative rhythm disturbances.

A method of decreasing anastomotic leaks and delivering cardioplegia in aortic root replacement

Ascending aortic root replacement is associated with a significant incidence of bleeding from composite graft to annulus anastomosis and from coronary to composite anastomosis. We describe a technique for composite graft to annulus and coronary to composite graft anastomoses with circular Teflon donuts. We also describe a method for delivery of antegrade cardioplegia that allows assessment of anastomoses prior to weaning from bypass.

Aggressive blood conservation in coronary artery surgery: impact on patient care

Data on 100 consecutive non-emergency coronary artery bypass (CABG) patients were analyzed retrospectively. Sixty-nine patients received no homologous blood (Group I). Thirty-one patients received a total of 118 units of blood products averaging 2.23 units of red cells (Group II). The average red cell transfusion rate for all patients was 0.7 units per patient. The median age for Group I was 61 and Group II was 68 years (p less than 0.05). The average number of grafts was the same for both (3 per patient) with 75% of Group I and 58% of Group II receiving internal mammary artery (IMA) grafts (p less than 0.05). Twelve of the Group II patients who received intraoperative transfusions on cardiopulmonary bypass to maintain adequate hemoglobin levels were older and had lower admission hematocrits: 36 +/- 0.8% compared to 41 +/- 0.5% for all other patients (p less than 0.05). Average postoperative blood loss was 889 +/- 38 ml for Group I and 1077 +/- 104 ml for Group II (p less than 0.05). Increased hemorrhage was correlated with bypass time and IMA use but not with preoperative heparin administration, pre-existing risk factors (diabetes, hypertension, etc.), bleeding time, post-bypass clotting time, age or number of grafts. Two patients in Group II and none in Group I required exploration for excessive postoperative hemorrhage. Mortality rate was 2% (both in Group II, neither transfusion related). Discharge hematocrits were the same for all at 29.4 +/- 0.4%. Among anemia-related postoperative symptoms, only sinus tachycardia was significantly higher in Group I (20%) compared to Group II (6.5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Early reexploration for excessive postoperative bleeding lowers wound complication rates in open heart surgery

Clinical reviews of sternal wound infections following open heart surgery indicate many predisposing factors including diabetes, low cardiac output, use of bilateral internal mammary grafts, and reoperation for excessive postoperative bleeding. This study was undertaken to determine the role of mediastinal re-exploration in the development of sternal wound complications. From a series of 2,271 patients undergoing median sternotomy for open-heart surgery between 1979 and 1984, 71 (3.1%) were re-explored for excessive bleeding. Nine of these patients died in the early postoperative period of noninfectious complications. The remaining patients were divided into two groups. Group 1 (54 patients) were re-explored without subsequent problems. Group 2 (8 patients) developed sternal and costochondral wound complications. Comparison of age, intercurrent and pre-existing disease, total bypass time, crossclamp time, and postoperative hemodynamic status showed no statistical difference. All patients bled an average rate of 247 ml/hr. However, the average time before re-exploration was 7.6 hours in group 1 compared to 13.8 hours in group 2 (P less than 0.001). Sternal wound complications may be minimized by a policy of early re-exploration for excessive postoperative bleeding (greater than 200 ml/hr for 4 hours).

An eight-year experience with porcine bioprosthetic cardiac valves

A total of 589 porcine bioprostheses were implanted in 509 patients from January, 1976, through December, 1983. Of the valves implanted, 390 were Hancock and 199 were Carpentier-Edwards. A total of 1,633 patient-years was accrued, with a mean follow-up of 38 months per patient. Two hundred eight patients had aortic valve replacement, 209 had mitral valve replacement, and 79 had multiple valve replacements, of which 46 were aortic and mitral replacements. The mortality for isolated aortic valve replacement was 5.8%; for isolated mitral replacement, 8.6%, and for all patients, 10.9%. Late mortality was 3.9% per patient-year. The actuarial survival rate at 5 years was 79% for aortic, 68% for mitral, and 76% for aortic-mitral valve replacement. There were 12 thromboembolic events (0.73% per patient-year). Two episodes occurred in patients with an aortic bioprosthesis, nine in patients with a porcine mitral valve, and one in a patient with mitral and tricuspid bioprosthetic valves. The probability of remaining free of thromboembolism at 5 years was 99% for the group having aortic valve replacement, 93% for those having mitral replacement, and 100% for the group having aortic-mitral valve replacements. Thirteen episodes of endocarditis occurred (0.8% per patient-year). Seven of the 13 patients died as a direct result of endocarditis. The probability of remaining free of prosthetic endocarditis at 5 years was 97% for the aortic valve replacement group, 95% for the mitral group, and 97% for the aortic-mitral group. There were 20 instances of xenograft failure (1.2% per patient-year). The probability of remaining free of valve failure at 5 years was 96% for the aortic valve replacement group, 93% for the mitral group, and 93% for the aortic-mitral replacement group. Primary tissue failure of a prosthesis occurred in seven patients, all with Hancock valves (0.43% per patient-year). As yet there has been no primary tissue failure of the Carpentier-Edwards prosthesis. There also appears to be a lower incidence of thromboembolism (Edwards, 0.3% per patient-year; Hancock, 0.8% per patient-year) and endocarditis (Edwards, 0.6% per patient-year; Hancock, 1.0% per patient-year). The low incidence of complications with the porcine bioprosthetic valve, especially the Carpentier-Edwards, encourages us to recommend its continued use, especially in situations in which anticoagulation is contraindicated.

Complete surgical revascularization: the treatment of choice in young patients with multivessel coronary disease

Since the advent of coronary angioplasty, nonoperative techniques to manage coronary artery disease have become attractive alternatives to coronary artery bypass grafting (CABG). To provide a standard against which new procedures could be judged, 123 consecutive patients less than 45 years of age who have had CABG since 1978 were systematically followed. The indications for operation were unstable angina or postinfarction angina (60%), life-threatening coronary anatomy with stable angine (36%), and sudden death or uncontrolled ventricular tachycardia (4%). Seventy-five patients had documented preoperative myocardial infarction, 55% within 30 days of CABG. An average of 3.2 vessels were grafted per patient; only 10 had single CABG. Complete revascularization was accomplished in 91% of patients. Five patients (4%) had myocardial infarction within 30 days of operation. No operative deaths or strokes occurred. The 6-year follow-up was 94.4% (the 5-year actuarial survival rate, 87.4%). There were four late deaths; two were due to myocardial infarction, one to prosthetic valve failure, and one to sudden death. At 2.7 years, 88.1% of the patients were NYHA Functional Class I; 85.4% continued full-time employment, and 98% considered their quality of life the same or better than before CABG. Five patients suffered myocardial infarctions during the follow-up period. Nine patients required reoperation: eight for graft occlusion (three less than 1 year, five greater than 3 years), and one for disease progression. These data confirm that complete operative revascularization remains the standard of therapy for young patients with multivessel coronary artery disease as evidenced by the absence of early mortality, the low incidence of morbidity, the excellent functional recovery, and the high return to gainful employment.

Interhospital transport of patients with ongoing intraaortic balloon pumping

During a 5-year period (1979 to 1983), 50 consecutive patients undergoing continuous intraaortic balloon (IAB) pumping were transferred from Evanston Hospital to Northwestern Memorial Hospital (16 miles), where they underwent cardiac operation. All patients had cardiac catheterization before transfer. Indications for IAB were cardiogenic shock (9 patients), postinfarction angina (18 patients), unstable angina (9 patients), evolving myocardial infarction (3 patients), accelerating angina or hemodynamic instability during cardiac catheterization (9 patients) and prophylactic insertion for high-grade left main stenosis (2 patients). Transportation after stabilization was uneventful in all patients. All patients underwent operative coronary revascularization. There was concomitant mitral valve replacement in 3 patients, acute ventricular septal defect repair in 1 patient, aortic valve replacement in 1, and ventricular aneurysmectomy in 1. Three patients (5%) died postoperatively. Nine patients (20%) had complications directly related to IAB insertion. One patient required femoral-femoral arterial bypass preoperatively, 4 patients had postoperative lower limb ischemia treated by IAB removal or thrombectomy and 1 patient had thrombocytopenia (less than 60,000/mm3), 1 false aneurysm, 1 anterior compartment syndrome and 1 prolonged bleeding at the insertion site. Interhospital transfer with IAB pumping in progress should not be restricted to patients with cardiogenic shock, but can be effectively used for all patients who require preoperative IAB insertion.(ABSTRACT TRUNCATED AT 250 WORDS)

Management of chronic sternal osteomyelitis

The management of 2 patients in whom chronic sternal osteomyelitis developed after apparently uncomplicated coronary artery bypass operations is described. Each patient had become totally disabled because of chronic, draining sinus tracts. Eradication of the infection required total sternectomy and excision of all infected costal cartilage. Subsequent reconstruction was accomplished by using bilateral pectoralis major myocutaneous advancement flaps without any maneuvers to stabilize the anterior chest wall. Both patients have resumed full activity and have returned to work with only minimal residual compromise of pulmonary function.

A simplified technique for grafting the first septal perforating branch of the left anterior descending coronary artery

A technique for facilitating the identification and grafting of the first septal perforating branch of the left anterior descending coronary artery is described. This technique makes endarterectomy of the vessel unnecessary.

Cardiac and renal responses to cross-clamping of the descending thoracic aorta

The present study was performed to document the relative efficacy of commonly applied techniques used adjunctively during 1 hour of descending thoracic aortic cross-clamping. Renal and cardiac responses were determined by standard laboratory methods. There were four experimental groups: (1) heparin-bonded shunt; (2) partial femoral-femoral bypass; (3) sodium nitroprusside; (4) control. Each of the experimental groups showed abnormal hemodynamic responses during cross-clamping. Elevations in left ventricular end-diastolic pressure (LVEDP) and systolic blood pressure were common events during clamping, and cardiac output often decreased. Nevertheless, left ventricular performance curves after cross-clamping showed similar increases in left ventricular stroke work (LVSW) with increasing preload. In addition, left ventricular biopsy specimens showed preservation of myocardial high-energy phosphate stores and essentially normal ultrastructural integrity. Radioactive microspheres generally showed increased myocardial blood flow during and after cross-clamping, but no evidence of preferential subendocardial ischemia. Examination of renal function showed a marked decrease in urine output, glomerular filtration rate, and renal plasma flow during cross-clamping. Following the release of the cross-clamp, renal function returned to 50% to 85% of baseline status. Since we could find no major advantage of any of the techniques employed under the present experimental conditions, we suggest that all of the techniques should be part of the surgical armamentarium and the particular preoperative and/or intraoperative findings in a specific case should determine which technique is most appropriate for a given patient.

Operative therapy of malignant ventricular rhythm disturbances

Pre- and postoperative electrophysiologic study (EPS), intraoperative cardiac mapping, and extended endocardial resection of scar (EER) has enabled us to identify subgroups among 94 patients who have had operation to control or prevent malignant ventricular arrhythmia. Operative mortality was 8.5% and cure or prevention of ventricular arrhythmia was accomplished in 92% of survivors. Group 1: 13 patients were resuscitated from "sudden death" due to ventricular fibrillation (VF). All had exercise-induced VF and/or ventricular tachycardia (VT). Preoperative EPS revealed no inducible VT/VF. All had coronary artery disease, without evidence of myocardial infarction (MI) or ventricular wall motion abnormality; all were cured with conventional myocardial revascularization. Group 2: 65 patients had MI with residual left ventricular wall motion abnormality, usually aneurysm. The malignant arrhythmia, either sustained VT (38 patients) or VF (27 patients), was inducible by EPS but not usually by exercise, and all were refractory to medical therapy. Treatment was operative mapping, aneurysmectomy, EER, and coronary revascularization. Operative mortality was 11.9%; 90% of survivors are arrhythmia free, off drugs; 10% are now drug responsive. Group 3: 3 patients without coronary disease had VT or VF caused by endocardial sarcoidosis or operative scar from a previous congenital heart operation. Treatment was EPS, operative mapping, and excision of abnormal endocardial scar with no operative mortality. Group 4: 13 patients underwent aneurysmectomy for indication other than arrhythmia, but had preoperative ventricular irritability which was not life-threatening. Operation was aneurysmectomy, prophylactic EER, and revascularization with no mortality and no postoperative arrhythmic events. After many years of unpredictable and unsatisfactory results from various empirical surgical approaches, the operative treatment of malignant ventricular arrhythmia is now based on sound electrophysiologic principles.

Changes in left ventricular performance related to perioperative myocardial infarction in coronary artery bypass graft surgery

Strict electrocardiographic, enzymatic, scintigraphic, and hemodynamic criteria for perioperative myocardial infarction (MI) were defined and related to serial assessments of left ventricular performance during rest and exercise in patients seen early and late after coronary artery bypass graft operation. Global left ventricular performance was determined by radionuclide ventriculography from which changes in the pattern of serial postoperative ejection fractions (EF) were obtained. Patients were divided into two groups based on the presence or absence of perioperative MI, and were matched in pairs on the basis of preoperative EF and extent as well as location of coronary artery obstructions. The results indicate that neither short- nor long-term depression in resting EF occurred subsequent to perioperative MI. However, an exercise-related increase in EF eight months postoperatively was depressed in patients who had perioperative MI compared with those who did not. Patients with new Q waves and abnormal postoperative elevation in serum levels of the myocardial isoenzyme of creatine kinase (CK-MB) had a greater early decrease in EF compared with patients without evidence of perioperative MI. However, seven days after operation, the EF in both groups returned to preoperative levels. Patients with abnormal technetium 99m-pyrophosphate scintigrams had changes in perioperative EF similar to those in patients without MI. The presence of low cardiac output syndrome immediately after operation was associated with immediate and short-term decreases in EF, which were not seen in any of the other patient subgroups.

The efficacy of medical stabilization prior to myocardial revascularization in early refractory postinfarction angina

The timing of coronary artery bypass graft (CABG) surgery in patients with persistent, severe myocardial ischemia after an acute myocardial infarction is controversial. Based on the previous disappointing clinical experience with urgent surgery, a period of medical stabilization (mean ten days, range two to 28) prior to surgery was employed in a prospective nonrandomized clinical trial. The frequent use of intravenous nitroglycerin and intra-aortic balloon pumping was important in allowing preoperative clinical stabilization in these patients who were refractory to conventional medical therapy. The combined medical-surgical treatment protocol was associated with no early or late mortality in 20 patients who suffered preoperative myocardial infarction and demonstrated refractory post-infarction angina. Although these patients were considered to be high-risk surgical candidates, the incidence of perioperative myocardial damage in this selected group was comparable with that observed in patients undergoing elective CABG surgery at this institution without recent preoperative myocardial infarction. In order to determine the hemodynamic effectiveness of this selected patient management process, perioperative changes in left ventricular performance were determined by multigated cardiac blood pool imaging. Computer-based analysis of this radionuclide-related data allowed the accurate determination of ejection fraction (EF). Those patients with preoperative subendocardial infarction (N = 12) had no decrease in global EF 24 hours after operation and significant increases in EF seven days and eight months after operation. This pattern is analogous to that observed in patients without preoperative myocardial necrosis undergoing elective CABG surgery at this institution. Those patients with recent preoperative transmural myocardial infarction (N = 8) showed a decrease in EF 24 hours after operation, but recovered to preoperative levels seven days and eight months after operation. There was, however, no increase in EF in this subgroup of patients. On the basis of this study, the authors tentatively recommend a concerted effort at preoperative medical stabilization prior to CABG surgery in patients with persistent refractory myocardial ischemia soon after acute myocardial necrosis. A prospective, randomized study comparing urgent and delayed surgery, as well as nonsurgical treatment, will be necessary to define more precisely optimal management of this subgroup of cardiac patients.

Extended endocardial resection for the treatment of ventricular tachycardia and ventricular fibrillation

A total of 40 patients with drug-refractory, life-threatening cardiac rhythm disturbances--ventricular tachycardia in 23 patients and ventricular fibrillation in 17 patients--underwent extended endocardial resection (EER) of scar tissue. Scarring was due to myocardial infarction in 38 patients, to previous congenital heart operation in 1 patient, and to sarcoidosis of the heart in 1. The EER procedure was directed by epicardial and endocardial mapping data whenever possible, and was usually combined with revascularization, aneurysmectomy, or, in 5 patients, mitral valve replacement. Operative mortality was 10%, incident to poor preoperative ventricular function and hemorrhage secondary to previous cardiac surgical procedures. Thirty-three of the 36 survivors (92%) are free of arrhythmia at follow-up periods ranging from 3 to 36 months (mean, 12.5 months); the arrhythmia in the remaining 3 patients is now drug controlled. Thirty-three patients had postoperative electrophysiological studies, and in 30 (91%), the arrhythmia was no longer inducible. The results of surgical treatment for ventricular tachycardia and ventricular fibrillation were similar. The results also proved satisfactory whether the EER procedure was directed by visual observation or mapping.