The empirical foundations of telemedicine interventions for chronic disease management

The telemedicine intervention in chronic disease management promises to involve patients in their own care, provides continuous monitoring by their healthcare providers, identifies early symptoms, and responds promptly to exacerbations in their illnesses. This review set out to establish the evidence from the available literature on the impact of telemedicine for the management of three chronic diseases: congestive heart failure, stroke, and chronic obstructive pulmonary disease. By design, the review focuses on a limited set of representative chronic diseases because of their current and increasing importance relative to their prevalence, associated morbidity, mortality, and cost. Furthermore, these three diseases are amenable to timely interventions and secondary prevention through telemonitoring. The preponderance of evidence from studies using rigorous research methods points to beneficial results from telemonitoring in its various manifestations, albeit with a few exceptions. Generally, the benefits include reductions in use of service: hospital admissions/re-admissions, length of hospital stay, and emergency department visits typically declined. It is important that there often were reductions in mortality. Few studies reported neutral or mixed findings.

Teleconsultation practice guidelines: report from G8 Global Health Applications Subproject 4

This report presents a series of recommendations derived from deliberations of the G8 countries Subproject 4 Group (SP4 Group) of the Global Health Care Applications Project entitled, A Teleconsultation Practice Guideline. The recommendations provide an initial step toward developing a general guideline platform for the practice of telemedicine/teleconsultation.

International concerted action on collaboration in telemedicine: recommendations of the G-8 Global Healthcare Applications Subproject-4

The main objectives of the G-8 Global Healthcare Applications Subproject-4 (G-8 GHAP-SP-4) were to establish an international concerted action on collaboration in telemedicine, telehealth, and health telematics (hereafter referred in this paper as telemedicine). In order to promote and facilitate the implementation of telemedicine or health telematics networks around the world, it was considered necessary to address certain key issues. Five thematic solution-seeking forums were held between May 1998 and December 1999. Each addressed a key issue, including interoperability of telemedicine and telehealth systems, impact of telemedicine on health care management, evaluation and cost effectiveness of telemedicine, clinical and technical quality and standards, and medico-legal aspects of national and international applications. The main objectives of these forums were to establish best practices and a thorough review of the issues and discussions among experts to determine the best solutions for the facilitation of global international telemedicine networks. More than 650 invited participants from 16 countries attended the five forums, which were of 2-3 days in duration. These forums provided a foundation for the exchange of ideas resulting in the initiation of collaborative activities. Based on these deliberations, a series of 21 recommendations were prepared by the national representatives of the G-8 GHAP SP-4. These recommendations propose to political leaders and health care managers of the G-8 and other countries roadmaps to follow in order to accelerate the achievement of a Global Society of Healthcare via Telemedicine, Telehealth, and Health Telematics. The 21 recommendations are presented in this report.

Pitfalls in surgical decision-making during mitral valve repair

Mitral valve repair has become the mainstay of surgical treatment for mitral valvular regurgitation. Surgeons in North America were relatively slow to adopt the various repair techniques, perhaps because rheumatic heart disease was less common, and the initial experiences with large numbers of repairs in Europe dealt largely with rheumatic disease. Subsequent experience, however, has clearly shown that patients with degenerative mitral valve disease can expect very durable repairs, and that most such patients have relatively simple pathologic conditions. The potential for repair, with a lack of need for long-term anticoagulation, has led to earlier surgical intervention. Still, mitral valve repair is far more complex than mitral valve replacement and must be accompanied by careful intraoperative decision making. Pitfalls exist that are different from those that accompany replacement. In this article, we examine some of the more common problems, their identification, and, hopefully, ways to avoid them.

Improved in-hospital mortality in women undergoing coronary artery bypass grafting. Northern New England Cardiovascular Disease Study Group

BACKGROUND

Few studies have examined the changes in in-hospital mortality for women over time. We describe the changing case mix and mortality for women undergoing coronary artery bypass grafting (CABG) from 1987 to 1997 in northern New England.

METHODS

Data were collected on 8,029 women and 21,139 men undergoing isolated CABG. The study consisted of three time periods (1987 to 1989, 1990 to 1992, and 1993 to 1997) to account for regional efforts to improve quality of care that occurred during 1990 to 1992.

RESULTS

Compared with 1987 to 1989, women undergoing CABG in 1993 to 1997 were older, had poorer ventricular function, and more often required urgent or emergency operations. The crude and adjusted mortality rates for both women and men decreased significantly over time. The absolute magnitude of the change in adjusted rates was greater for women (3.1%) than for men (1.5%). Although women represented only 28% of the study population, the decrease in their mortality accounted for 44% of the total decrease in adjusted mortality during the study period.

CONCLUSIONS

Over the last decade there has been a marked decrease in CABG mortality for women, despite a worsening case mix.

Risks of morbidity and mortality in dialysis patients undergoing coronary artery bypass surgery. Northern New England Cardiovascular Disease Study Group

BACKGROUND

Although dialysis patients are undergoing CABG with increasing frequency, large studies specifically comparing patient characteristics and procedure-related risks in this population have not been performed.

METHODS AND RESULTS

We conducted a regional prospective cohort study of 15,500 consecutive patients undergoing CABG in northern New England from 1992 to 1997. We used multiple logistic regression analysis to examine associations between preoperative dialysis-dependent renal failure and postoperative events and to adjust for potentially confounding variables. The 279 dialysis-dependent renal failure patients (1.8%) were 4.4 times more likely to experience in-hospital mortality than were other CABG patients (12.2% versus 3.0%, respectively; P:<0.001). Dialysis-dependent renal failure patients were older and had more comorbidities and more severe cardiac disease than did other CABG patients. After adjusting for these factors in multivariate analysis, however, dialysis-dependent renal failure patients remained 3.1 times more likely to die after CABG (adjusted odds ratio [OR] 3.1, 95% CI 2.1 to 4.7; P:<0.001). Dialysis-dependent renal failure patients compared with other CABG patients also had a substantially increased risk of postoperative mediastinitis (3.6% versus 1.2%, respectively; adjusted OR 2.4, 95% CI 1.2 to 4.7; P:=0.011) and postoperative stroke (4.3% versus 1.7%, respectively; adjusted OR 2. 1, 95% CI 1.1 to 3.9; P:=0.016), even after controlling for potentially confounding variables. Risks of reexploration for bleeding were similar for patients with and without dialysis-dependent renal failure.

CONCLUSIONS

Preoperative dialysis-dependent renal failure is a strong independent risk factor for in-hospital mortality and mediastinitis after CABG.

Challenges to the implementation of telemedicine

In the United States, we are witnessing a renewed emphasis on the potential role of telemedicine in redressing issues of accessibility, cost, and quality of medical care. This paper describes several major problems confronting the current generation of telemedicine projects as they move toward maturity. In fact, it is argued here, the future development of telemedicine as an integral component of the health care system depends on the successful resolution of these concerns. Included for discussion are issues related to physicians, institutions, patients, and the general public. On the basis of the tenets of telemedicine and its capacity to transcend traditional boundaries of medical care via telecommunications, informed speculations are presented that are intended to stimulate discussion and provide direction for addressing a number of potential problems. Included are suggestions pertaining to restructuring the medical licensure system to accommodate telemedicine and the virtual regionalization of health care; implications for provider liability and reimbursement; patient privacy; system design; and diffusion of information.

Telemedicine: where it is and where it's going

The term telemedicine encompasses a wide range of telecommunications and information technologies and many clinical applications, although interactive video may be the most common medium. The first telemedicine programs were established almost 40 years ago, but the technology has grown considerably in the past decade. Despite the expansion of telemedicine, the volume of patients receiving services that use the technology remains relatively low (about 21000 in 1996). In part, this reflects the lack of a consistent coverage and payment policy and concerns about licensure, liability, and other issues. A considerable amount of federal funding has supported telemedicine in recent years, and legislators and federal, regional, and state policymakers are struggling with several crucial policy matters. Research on the effectiveness of telemedicine is somewhat limited, although the work that has been done thus far supports the hypothesis that, in general, the technology is medically effective. The cost-effectiveness of specific telemedicine applications has not yet been rigorously demonstrated.

A proposed framework for economic evaluation of telemedicine

Economic evaluation of telemedicine compares the costs and other consequences of delivering specific services through telemedicine vs. alternative means. Cost-effectiveness analysis, the most common method used for health issues, helps to assess whether the expected health benefits are worth the investment. Telemedicine raises particular challenges for evaluators: a telemedicine system may have multiple uses and joint costs that are difficult to apportion to one service, the existence of a system may lead to expanded indications for use, and technological change may rapidly make an evaluation outdated. Public and private regulation and payment may affect the diffusion of telemedicine. Uncertainty surrounds the policy of the U.S. Food and Drug Administration, which is still formulating its position. Changes are underway in policies on licensure and credentialing of clinicians, which have traditionally been done by state and by site, to reflect the fact that telemedicine services may cross these regional boundaries. Lack of insurance coverage for telemedicine services has been considered an impediment to adoption with fee-for-service payment. Under capitation payment and fixed budgets, however, providers have financial incentives to use the most efficient method to deliver services, and these arrangements would favor telemedicine if it is the less costly alternative. If telemedicine were most costly and the health benefits worth the cost, monitoring might be needed to ensure the quality of care.

Hybrid myocardial revascularization after previous left pneumonectomy

Previous intrapericardial left pneumonectomy and irradiation necessitated an unorthodox, staged approach to myocardial revascularization in a patient with unstable angina pectoris, left main artery, and three-vessel coronary artery disease. A saphenous vein bypass graft was constructed from the descending thoracic aorta to the left anterior descending coronary artery via left thoracotomy, without cardiopulmonary bypass. Two days later the patient underwent stenting of the left main and circumflex coronary arteries. Recovery was uneventful.

Expanding indications for pediatric coronary artery bypass

Pediatric coronary artery bypass has been done mostly for ischemic complications of Kawasaki disease. We reviewed our clinical experience between 1987 and 1994 with internal thoracic artery-coronary artery bypass in one infant and five children for varying indications. Indications for coronary bypass included Kawasaki disease (2), congenital left main coronary ostial stenosis, iatrogenic coronary cameral fistula, anomalous origin of the left coronary artery from the pulmonary artery, and single coronary artery traversing between the great arteries in a patient after cardiac transplantation. An additional cohort of 34 control patients of various ages and weights (1 day to 16.1 years, 2.6 kg to 62 kg) had angiographic measurements of the right coronary, left coronary, and left internal thoracic arteries with respect to the feasibility of performing coronary artery bypass. All six patients survived internal thoracic artery-left anterior descending coronary artery bypass without evidence of perioperative myocardial infarction. Postoperative angiographic studies in five and color Doppler echocardiography in one showed graft patency. Retrospective angiographic measurements in the 34 control patients showed that internal thoracic and coronary arteries are proportionately quite large in neonates and infants compared with those in older children and adolescents. Internal thoracic artery-coronary artery bypass should be considered for the expanding indications presented herein and when emergency intraoperative life-threatening situations present themselves. Long-term patency and reoperation rates have yet to be determined.

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.