Donald W. Miller

Does Preservation of the Posterior Chordae Tendineae Enhance Survival during Mitral Valve Replacement

During a 30-month period, 51 patients underwent mitral valve replacement. There were 3 hospital deaths (5.9%), 2 of which were due to ventricular rupture. The 3 patients who died were among 13 patients in whom mitral valve replacement was combined with tricuspid or aortic valve operation or both. Postmortem findings in the 2 patients who died of ventricular rupture showed that the ventricular tears were located between the atrioventricular groove and the unresected papillary muscle stumps, in an area of ventricle formerly tethered by the posterior chordae tendineae. In the last 14 patients in the series, the posterior leaflet of the mitral valve and its chordae tendineae were left intact, and there was no mortality or prosthetic valve dysfunction. In patients with myxomatous or ischemic disease, the posterior leaflet was left completely intact. For patients with fibrocalcific rheumatic disease, we have developed a technique of partial excision and debridement of the posterior leaflet, preserving the intermediate and basal chordae tendineae attachments. With the techniques described, preservation of all or part of the posterior leaflet and its chordae tendineae does not appear to interfere with prosthetic valve function and, by reducing the risk of ventricular rupture, should enhance survival after mitral valve replacement.

Omental Pedicle Graft in the Management of Infected Ascending Aortic Prostheses

Two patients had mediastinal infections with chronic draining sinus tracts that involved a vascular prosthesis in the ascending aorta. In 1 patient, a false mycotic aneurysm developed and in the other, a beginning rupture of the proximal suture line. In both patients, the infection was cured by replacing the infected aortic prosthesis combined with wrapping the new prosthesis with a pedicled omental graft. An omental graft was used to protect the vascular prosthesis and minimize the risk of recurrent infection.

Anterior sternal retraction for reoperative median sternotomy

The incidence of reoperative median sternotomy for repeat cardiac surgery is increasing. Reoperative median sternotomy is associated with a higher morbidity and mortality than first-time cardiac surgery. A portion of this morbidity and mortality may be due to direct injury to the heart and great vessels in the process of reopening the sternum. We report a new technique utilizing anterior sternal retraction that allows division of adhesions between the undersurface of the sternum and the heart and great vessels under direct vision. This technique enables the surgeon to minimize the risk of serious injury to these underlying structures during reoperative cardiac surgery.

Improved Anesthesia for Deep Surface-Induced Hypothermia: The Halothane-Diethyl Ether Azeotrope

The halothane-diethyl ether azeotrope was evaluated in dogs as the anesthetic agent for deep surface hypothermia with total circulatory arrest for open-heart operation. All 10 animals given azeotrope in 100% oxygen (O2) experienced atrial arrhythmias during cooling, and 1 had ventricular fibrillation prior to the completion of cooling at 18 degrees to 20 degrees C. After only 30 minutes arrest, 8 of the 10 dogs had postoperative motor disturbances. Administering the azeotrope in 95% O2 and 5% carbon dioxide (CO2) yielded markedly improved results characterized by a rapid, smooth cooling course, easy resuscitation following circulatory arrest, and rapid rewarming, and 3 out of 10 dogs experienced mild motor disturbance after 60 minutes of circulatory arrest. This method, when compared with our standard method of ether in 100% O2, resulted in reduced blood lactates and a striking improvement in clinical status on the first postoperative morning. In limited clinical trials, infants undergoing repair of congenital cardiac defects have done well and responded as expected based on the laboratory experience. Since the results with the azeotrope in 95% O2 and 5% CO2 were at least as good as, and in several instances better than, those with the standard method employing either, the nonexplosive characteristic of the azeotrope warrants continued evaluation of this agent.

No scientific support for linking dietary saturated fat to CHD.

Pedersen et al. express concern that recently published research had downplayed the importance of SFA consumption as a risk factor for CHD. Their main argument is that prospective cohort studies are unreliable. There are of course uncertainties in such studies, but it is difficult to ignore that more than thirty cohort studies have shown that patients with CVD did not eat more SFA than had hearthealthy people; in six of them, stroke patients had actually eaten less. To make their case, Pedersen et al. presented a small and biased subset of ecological studies apparently linking reduced consumption of SFA to a low incidence of CHD. However, they neglected to mention the many ecological studies that have documented findings from groups with a high consumption of SFA, but with low rates of CHD, including Masai people, French, Italian-Americans and Polynesians. They also claim that the association between the decline of CHD mortality in Finland and the lowered intake of SFA was causal. However, the decline began in North Karelia 3 years before the start of the cholesterol campaign, and it occurred also in the districts where no advice was given. Pedersen et al. asserted that SFA with twelve to sixteen carbon atoms are the most potent LDLand total cholesterolraising fatty acids. However, other researchers reported that the serum content of these fatty acids is inversely associated with serum cholesterol, and in seven studies, the content of twelve to sixteen carbon fatty acids in the blood or the fat cells was similar or lower in patients with acute CHD than in healthy people. The content of certain SFA in the serum reflects the intake of dairy fat, and such intake is inversely associated with BMI, waist circumference, ratio of LDL:HDL and fasting glucose concentration, and positively associated with HDL and apoA-I. In accordance, a meta-analysis of twenty-five cohort studies showed that the lowest total mortality, cardiovascular incidence and mortality, and incidence of diabetes were seen among those with the highest intake of dairy fat. Pedersen et al. endorse the many reports emphasising the importance of increasing the intake of PUFA. This advice is not based on randomised, controlled dietary trials, because no such trial has ever succeeded in lowering cardiovascular or total mortality by exchanging SFA with PUFA. Rather, the advice is based on statistical calculations using data from unreliable cohort studies. Pedersen et al. refer to a meta-analysis of such trials, the authors of which claimed benefit, but they had excluded two trials, where CHD mortality had increased in the treatment groups, and included a trial where a decreased risk was seen only in the participants who increased their intake of fish, and also the Finnish Mental Hospital Study, a trial which does not satisfy the quality criteria for a correctly performed randomised controlled trial. A reduction of SFA was part of the intervention in three multifactorial trials, but these trials were unsuccessful as well; in one of these, total mortality was twice as high in the treatment group. Numerous studies on laboratory animals and human subjects have also shown that an increased intake of PUFA, in particular of the n-6 type, is associated with many adverse health effects such as allergy, asthma, immunosuppression, decreased fertility, pre-eclampsia, encephalopathy and cancer. In accordance with this, Israeli Jews have a high intake of the ‘recommended’ n-6 type of PUFA (from grains and soyabean oil), and they exhibit a high incidence of cancer and CHD mortality compared with other Western countries. In conclusion, Pedersen et al. do not provide sufficient evidence to implicate SFA in CHD risk. There is increasingly strong evidence that SFA are not involved.

Bergen and Seattle: A tale of strategic planning in two cities

Abstract Strategic planning, as developed in the military and business sectors, offers a procedural model with important differences from the earlier comprehensive approach. Economic and physical development strategies, often called for by national planning legislation in European countries, frequently have little in common with the model proposed by Steiner for private firms, or espoused for the public sector by Bryson and others: there appears to be confusion resulting from use of similar terms. This paper investigates efforts to employ at least the major features of strategic planning in two institutionally and culturally different contexts, nearly half a world apart. In Bergen, Norway, these principles have informed economic development planning and planning for a major district of the city. In the case of Seattle, Washington, USA, the new comprehensive plan is based on framework policies developed during a 2‐year public process, and now that the city‐wide plan is adopted, Seattle is turning to develo...

Saphenous Vein Aortocoronary Bypass Grafts: Surgical Techniques

The surgical techniques used for aortocoronary bypass grafting with segments of autogenous saphenous veins are now well-standardized, and are applied in a remarkably uniform manner nationwide. Although there is some variation in the techniques employed, in general each practicing surgeon performs the operation by a standardized technique.

The Clinical Course of Patients with Coronary Artery Disease

The large number of people in our society with intractable angina pectoris has stimulated surgeons over the last several decades to develop surgical procedures for its relief. These surgical efforts culminated in the development of coronary artery bypass surgery, which is the first operative procedure that can substantially improve myocardial blood flow. Along with relief of anginal symptoms one would expect that improved myocardial blood flow after bypass grafting would prevent myocardial infarction and ventricular arrhythmias and thereby extend survival of patients with coronary artery disease. If so, then it must be recognized that only a minority of people with advanced coronary atherosclerosis are forewarned of this life-threatening disease by symptoms of angina pectoris. We must therefore consider the other clinical manifestations of coronary artery disease and identify the factors which are predictive of survival.

Myocardial Protection during Bypass Surgery

Precise coronary artery bypass grafting requires a bloodless, motionless operative field, and various techniques of cardioplegia are used to obtain these operative conditions while systemic blood flow is provided by a heart-lung machine. The technique of ischemic arrest provides the most optimal operating conditions for construction of distal bypass graft anastomoses. Placement of a clamp across the ascending aorta interrupts coronary flow and produces ischemic cardiac arrest, permitting precise execution of distal coronary artery anastomoses under optimal conditions. Although the best interests of the patient are served when bypass grafts are sutured precisely into well-exposed, immobile and bloodless coronary arteries, the surgeon must not irreversibly damage the myocardium while attempting to revascularize it. Most surgeons have found that only ischemic (anoxic) cardiac arrest provides the operating conditions necessary for precise distal bypass graft anastomoses (Table 22),1 and have therefore striven to develop techniques which can best protect the myocardium during the ischemic interval.2

The Risks of Coronary Artery Bypass Surgery

Despite the complexity of bypass surgery using extracorporeal circulation and various techniques for myocardial protection and small-vessel anastomoses, surgical teams in more than 500 United States hospitals perform this operation daily with a high degree of success.1 As the benefits of bypass surgery come into sharper focus, it is also important to define the risks of surgery, both the immediate risks of operative death and complications, and the delayed risks of graft occlusion and possible acceleration of the underlying coronary disease due to the presence of a functioning bypass graft. Patients at increased risk can be identified by several factors evident from their clinical courses and arteriographic studies. Various unexpected catastrophic events, however, account for the majority of operative deaths seen in patients undergoing bypass surgery. Also, it is important to recognize that patent bypass grafts hasten occlusion of obstructive lesions in the proximal coronary artery, and this risk must be weighed against the risk of eventual graft closure.