Biomedical subjects

D H Dillard

Publications and source records attributed to D H Dillard.

At least 37 records · Page 2Linked to original sources

PubMed1977

Current practice of coronary artery bypass surgery. Results of a national survey.

A survey of techniques used in coronary artery bypass graft (CABG) surgery by 400 experienced cardiac surgeons is presented. These surgeons performed 41,000 CABG operations in 1975. A seventy-question survey form was answered by each surgeon on their techniques for cardiopulmonary bypass and myocardial preservation, choice of bypass conduit, and grafting techniques. We found that extracorporeal circulation is almost always used in CABG surgery. A wide divergence of practice exists in the use of left ventricular vents and in methods of myocardial protection during coronary artery grafting. A spectrum of graft suture techniques is employed, the most common being a running double-ended suture anastomosis with the end of the vein initially fixed only at its heel to the coronary artery. Only 23 surgeons (6 per cent) prefer the internal mammary artery (IMA) rather than saphenous vein, when feasible, as the bypass conduit of choice for CABG surgery.

Aorta↗

PubMed1977

Surgical correction in infancy to reduce mortality in transposition of the great arteries.

The mortality for infants with transposition of the great arteries (TGA) prior to the introduction of medical and surgical septostomy was over 80% by 6 months of age. The mortality has fallen recently, due to balloon atrial septostomy (BAS), but still exceeds 25% by 6 months of age in major centers. The cumulative mortality rises to 40% by 1 year of age with or without additional surgical atrial septectomy. In our center, 12 patients with an average age of 3 months were operated on for interatrial baffle correction of their TGA under surface-induced deep hypothermia. BAS had been done preliminarily in those patients without an adequate atrial communication. Ten of these 12 patients (83%) survived. These patients have been followed up from one month to eight years with an average follow-up of over four years. Surgical correction during infancy offers a better survival rate for infants with TGA than does medical management, with or without palliative surgery.

Ductus Arteriosus, Patent↗

PubMed1976

Heparinless, oxygenatorless perfusion rewarming following surface-induced deep hypothermia for open-heart surgery.

To facilitate perfusion rewarming without the use of total body heparinization or an oxygenator following open-heart correction with surface hypothermia, we divised a pump circuit. The circuit, totally primed with 100 c.c. of saline, consists of polyurethane-polyvinyl-graphite (PPG) coated Tygon tubes (with one end tapered by heat treatment) and a copper-coil heat exchanger. A roller pump was used to achieve partial bypass from the left atrium to the ascending aorta with flow rates up to 70 c.c. per kilogram per minute. Experiments in dogs resulted in rapid rewarming, immediate return of cardiac function, and hematologic alterations similar to those noted during surface rewarming. The safety of the method was also demonstrated. Prothrombin time, partial thromboplastin time, and platelet values returned to control levels upon rewarming, and no thromboemboli or bleeding problems were noted. Six clinical experiences were accumulated. Details of the method, hematologic and blood chemical analyses in dogs, and the first clinical trial in a 3-month-old infant with transposition of the great vessels are reported.

Animals↗

PubMed1975

Outcome analysis of surgical therapy for patients with angina pectoris.

Surgical therapy for coronary artery disease results in improved survival rates for selected groups of patients, particularly those with left ventricular dysfunction and/or severe coronary artery disease as evidenced by involvement of two or more vessels. Successful augmentation of coronary blood flow as shown by patient saphenous vein graft is associated with improved exercise tolerance when compared with patients in whom the grafts are occluded. Patients with impaired left centricular function as a result of their coronary artery disease appear to experience an improvement in this function with the augmentation of coronary blood flow by patent saphenous vein bypass grafts. In patients with occluded grafts and impaired left ventricular function, the left ventricular function is unchanged. Ptients with normal left ventricular function who sustain occlusion of their grafts will probably experience a reduction in their systolic ejection fraction.

Angina Pectoris↗

PubMed1975

Internodal conduction. Immediate and long-term effects of transverse circular incision of right atrium including atrial septum.

Immediate and long-term effects of a transverse circular incision of the entire right atrium, including the atrial septum, on internodal conduction were studied in 7 dogs. Electrocardiograms were followed up to 35 weeks, and the atrial epicardial excitation sequence was evaluated in all 7 dogs. The findings were compared with data from 3 normal dogs and 3 other dogs which underwent total atrial transverse incisions. All dogs with total atrial separation developed complete atrioventricular (A-V) block immediately after the operation and died within 3 days. All dogs with right atrial interruption exhibited persistent sinus rhythm with slight extension of P-R intervals and a normal QRS immediately after the operation. The mean P-R interval reached its maximum at the fourth day (50 per cent increase), remained prolonged through the first week, but returned to near control valves after 12 weeks. Three days later developed transient arrhythmia; sinus arrhythmia; sinus arrhythmia in 2 dogs and second-degree block in 1 appeared between the tenth and fourteenth postoperative days. Postoperative P vectors migrated toward the left. Atrial excitation sequence studies demonstrated prolongation of atrial epicardial conduction intervals (2.3 times) between the sinus node and distal right atrial wall. The presence of an interatrial conduction mechanism (whether by specific pathways or not), through which sinus node excitation was transmitted to the A-V node was demonstrated.

Animals↗

PubMed1975

Rheumatic mitral regurgitation. The case for annuloplasty in the pediatric age group.

Eight youngsters (five female, three male, ages 10 to 19 years, mean 15 years) with isolated severe rheumatic mitral regurgitation have been subjected to mitral annuloplasty because of limiting symptoms and prominent ECG and X-ray changes. They have been followed for up to 11 years (mean 3.7 years), and 7 have had excellent results. An early (1961) patient had a small annulus and was not a favorable candidate; he had only transient improvement. Seven are greatly improved, have decreased cardiac size (often dramatic), and have improved ECG's. One has undergone successful pregnancy, and none has been limited in activities. The extent and duration of improvement, lack of mortality, and resumption of normal activities by these youngsters indicate surgical success. The essence of childhood and youth is activity and the future life span hopefully long; hence, annuloplasty would appear to be the procedure of choice for severe rheumatic mitral regurgitation in the pediatric age group, avoiding the usual need for anticoagulation and uncertain long-term results associated with mitral valve replacement.

Adolescent↗

PubMed1974