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Biomedical subjects

F D Loop

Publications and source records attributed to F D Loop.

At least 55 records · Page 3Linked to original sources
PubMed1988

Coronary reoperations.

As coronary bypass surgery evolved from a procedure offered to good-risk patients into an intervention that is now applied to a spectrum of patients with many high-risk characteristics, so, too, reoperation for coronary surgery is now applied to an aging population with complicated atherosclerosis and abnormal left ventricular function. Despite our increased understanding of the factors that generate a need for reoperations and some potential avenues for preventing or delaying reoperations, the number of reoperations seems likely to increase. It is clear that the consistency of intraoperative myocardial protection must be improved; however, the favorable long-term results for these patients solidify the role of reoperation as an applicable intervention for patients with severe coronary atherosclerosis.

Aged↗
PubMed1988

Aortic valve replacement and coronary bypass grafting for patients with aortic stenosis and coronary artery disease: early and late results.

From 1967 to 1981, 294 patients (group A) with aortic stenosis and coronary atherosclerosis underwent aortic valve replacement (AVR) combined with bypass grafting; there were 13 (4.4%) in-hospital deaths. Follow-up of the in-hospital survivors documented late survival of 89%, 79%, and 52% at 2, 5, and 10 postoperative years, respectively. Univariate and multivariate testing identified age greater than or equal to 70 years (P = 0.02) and Class IV symptoms (P = 0.002) as factors decreasing late survival. Patients with bioprostheses who did not take warfarin had the best late survival (P = 0.03) and event-free survival (P = 0.05) and patients with mechanical prostheses who did not take warfarin had the worst (P less than 0.0001) (P = 0.001). From 1981 to 1986, 375 further patients (group B) with aortic stenosis and coronary artery disease underwent AVR and bypass grafting with 20 (5.3%) in-hospital deaths. Group B contained more patients greater than or equal to 70 years (35% vs. 16%) than did group A. Logistic regression analysis identified patients with moderate or severe impairment of left ventricular function and women as sub-groups with increased in-hospital mortality in group B. Patients with aortic stenosis and coronary artery disease can undergo AVR and bypass grafting with a risk slightly increased over that for isolated AVR. Bioprostheses enhance late survival and event-free survival.

Adult↗
PubMed1988

Survival of patients with mild angina or myocardial infarction without angina: a comparison of medical and surgical treatment.

A group of 390 patients with mild angina pectoris or myocardial infarction without subsequent angina had early coronary bypass operation. Five year survival was significantly higher (95.4%) than in a similarly selected medically treated group (88.5%) reported before. One death occurred in the 30 day postoperative period. Five year survival in the 179 patients who had internal mammary artery grafts was 98.9%. Survival for patients with mild angina and satisfactory left ventricular function (96.2%) was significantly higher than in the medical subset (91.3%). In the patient population studied, five year survival was higher in patients who had early bypass operations than in those who did not.

Adult↗
PubMed1988

Aortic valve replacement combined with myocardial revascularization. Late results and determinants of risk for 471 in-hospital survivors.

Among 500 patients consecutively undergoing primary aortic valve replacement combined with coronary bypass grafting from 1967 to 1981, there were 29 (5.8%) perioperative deaths. Follow-up of the late survivors ranged from 43 to 181 months (mean 85 months); actuarial survival rates were 88%, 77%, and 52% and event-free survival rates were 80%, 65%, and 32% at 2, 5, and 10 postoperative years. Cox proportional hazard analyses were used to identify determinants of late risk. Patient-related variables associated with decreased late survival rates included advanced age, cardiothoracic ratio 50% or greater, and preoperative New York Heart Association class III or IV symptoms. Moderate or severe impairment of left ventricular function as determined by angiography and advanced age were variables that decreased late event-free survival rates. Patients with bioprostheses had better survival rates (p less than 0.001) and event-free survival rates (p = 0.012) than did patients with mechanical valves. Analyses of subgroups according to the type of valve and postoperative anticoagulant management showed that both survival and event-free survival rates were decreased for patients with mechanical valves who were not taking warfarin and were enhanced for patients with bioprostheses who were not taking warfarin.

Aged↗
PubMed1988

Does bilateral internal mammary artery grafting increase surgical risk?

The risk of bilateral internal mammary artery grafting was studied in three groups of patients who were computer matched for recognized risk factors: year of operation, age, gender, extent of coronary artery disease, left ventricular function, completeness of myocardial revascularization, and history of congestive heart failure. The patient groups differed in the fact that they received veins only, one internal mammary artery graft, or two internal mammary artery grafts. The operative mortality rates for these three groups were 1.8%, 0.3%, and 0.9%, respectively (no significant difference). Analysis of perioperative morbidity demonstrated no significant differences except for a slight increase in transfusion requirements in the group receiving two internal mammary artery grafts (p = 0.04). None of the patients with only vein grafts had wound complications. One patient in the group with one internal mammary artery graft had a wound complication (0.03%). Eight patients receiving two internal mammary artery grafts had wound complications (2.4%) (p = 0.002). The prevalence of wound complications in patients with diabetes mellitus was 5.7% and in those without diabetes mellitus, 0.3% (p = 0.01). The prevalence of wound complications in patients less than 60 years of age was 0.2%, in patients in their 60s, 1.6%, and in patients older than 70, 3.1% (p = 0.01). Multivariate logistic regression analysis identified diabetes mellitus and age and not bilateral internal mammary artery grafting as risk factors for wound complications. We conclude that bilateral internal mammary artery grafting does not increase surgical mortality and increases surgical morbidity by a slight increase in the mean transfusion requirement.

Blood Transfusion↗
PubMed1987

Evaluation of normal prosthetic valve function by Doppler echocardiography.

Previous investigations have suggested that Doppler echocardiography is useful in detecting dysfunction in aortic (AVR) and mitral prostheses (MVR). However, to diagnose abnormalities, the spectrum of normal velocities through these valves must be established. Therefore, we used Doppler echocardiography to study 100 patients with 105 prosthetic valves that had no clinical evidence of valve dysfunction 9 +/- 8 days postoperatively. There were 66 Carpentier-Edwards (C-E), 23 St. Jude (S-J), and 16 Ionescu-Shiley (I-S) valves. In 70 AVR, the peak instantaneous gradient was 26.4 +/- 8.2 Hg, mean systolic gradient was 15.6 +/- 5 mm Hg, and gradients varied inversely with valve size, although differences were significant only when comparing the smallest vs the largest valve sizes (p less than or equal to 0.03). Peak instantaneous gradients greater than 36 mm Hg occurred only in AVR size 23 or smaller. There were no significant differences in gradients among C-E, S-J, and I-S AVR. In 35 MVR, mean gradient was 6.9 +/- 2.3 mm Hg and valve area was 2.7 +/- 0.8 cm2; neither varied significantly with valve size. However, S-J MVR group had smaller mean gradients and larger effective valve area than C-E bioprosthetic MVR (p = 0.01 and p = 0.05, respectively). Regurgitation was more common in AVR (26%) than in MVR (9%), p = 0.04, although all instances were mild and clinically silent. We conclude that normal AVR and MVR of a given size and type have a predictable range of Doppler echocardiographic parameters. Doppler evidence of mild regurgitation is a frequent finding in normal AVR and MVR.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Thoracic surgery manpower: the fourth manpower study of thoracic surgery: 1985 report of the Ad Hoc Committee on Manpower of The American Association for Thoracic Surgery and The Society of Thoracic Surgeons.

Responding to a survey about their practice in 1985, 2,969 (70%) Board-certified thoracic surgeons provided data that were compared with data from manpower surveys in 1980 and 1976. (table; see text) Thoracic surgeons were most active between ages 35 and 54 years when they accomplished 61% of all general thoracic and 85% of cardiac operations. Surgeons older than 50 years performed significantly more general thoracic operations than younger surgeons, and the younger group performed significantly more cardiac operations than their older counterparts. Solo practice continued to decline. In smaller referral areas, the number of general thoracic procedures per surgeon increased, but the number of cardiac operations have decreased compared with 1980. Overall, general thoracic and cardiac operations increased, but peripheral vascular procedures and pacemaker insertions decreased in almost all nine census regions. Fewer general thoracic and cardiac operations were performed per thoracic surgeon in the western United States than in central and eastern regions. In response to questions about work load, 55% believed that their clinical activity was satisfactory, 42% operated too little, and 3% operated too much. The 363 non-Thoracic Board-certified surgeons who responded performed 14% of general thoracic and 8% of cardiac surgery in 1985. During the first half of the 1980s, our specialty certified an average of 134 thoracic surgeons annually, which is higher than the 120 surgeons per year estimated to meet the projected demand.

Adult↗
PubMed1987

Fifteen hundred coronary reoperations. Results and determinants of early and late survival.

Fifteen hundred consecutive patients undergoing a first reoperation for coronary revascularization were reviewed to determine early and late results and predictors of survival. Patients were subdivided into cohorts on the basis of the year of reoperation: Group A (1967 to 1978, 436 patients); Group B (1979 to 1981, 439 patients); and Group C (1982 to 1984, 625 patients). Overall operative mortality was 3.4% (51 deaths): 4.6%, 2.3%, and 3.4% for Groups A, B, and C, respectively. Group C had significantly more women (p = 0.01) and patients with triple-vessel disease, left main coronary artery stenosis (greater than or equal to 50%), abnormal left ventricular function, age greater than or equal to 70 years, and graft failure as a surgical indication (all p less than 0.001). The mean interval between operations increased from 50 months for Group A to 84 months for Group C. At reoperation, Group C patients received more grafts, more internal mammary artery grafts, and had a higher prevalence of complete revascularization (all p less than 0.001). Univariate and multivariate analyses identified left main stenosis (p less than 0.0001), Class III or IV symptoms (p = 0.0002), advanced age (p = 0.0006), Group A (p = 0.02), and incomplete revascularization (p = 0.004) as predictors of increased in-hospital mortality. Follow-up of in-hospital survivors (mean interval 54 months, range 13 to 171 months) documented a 5 year survival rate of 90% and a 10 year survival rate of 75%. Multivariate testing identified advanced age (p less than 0.0001), hypertension (p less than 0.0001), and abnormal left ventricular function (p less than 0.0001) as predictors of decreased late survival.

Aged↗
PubMed1987

Elective coronary surgery.

The goal of providing patent grafts distal to important coronary stenoses remains unchanged. Results of bypass grafting show the influence of refined technique, improved technology, and the longer followup now available. Coronary artery bypass is now routinely performed with low morbidity and mortality. Late attrition of saphenous vein grafts with concomitant deterioration of patients' clinical status has been increasingly recognized. The internal mammary graft, with its superior patency and impact on length and quality of survival, is gaining wider acceptance. Increased use of the mammary artery graft and extension of its use with bilateral and sequential grafting patterns are an important trend in the current practice of coronary surgery.

Angina Pectoris↗
PubMed1987

Repeat mitral commissurotomy: long-term results.

Fifty-three patients underwent reoperation for open mitral commissurotomy (OMC) with one (1.9%) in-hospital death. The previous mitral operation was an OMC in 14 patients and a closed commissurotomy in 39. Mean age at the time of repeat OMC was 46 years (range 27 to 64), and NYHA functional class was II in 19 patients, III in 31, and IV in three. Follow-up of the 52 in-hospital survivors at a postoperative interval of 1 to 23 years (mean 10) documented 13 late deaths (mean interval 117 months, range 17 to 209) and survival of 96%, 83%, and 63% at 5, 10, and 15 postoperative years, respectively. Sixteen patients underwent subsequent mitral valve surgery (one OMC and 15 mitral valve replacements) 1 to 223 months after repeat OMC (mean 99), three patients within 5 years of repeat OMC. Reoperation-free survival was 94%, 74%, and 52% at 5, 10, and 15 postoperative years, respectively. Univariate testing did not document any correlation between age, functional class, rhythm, and either survival or reoperation-free survival. When feasible, repeat OMC can afford patients excellent long-term survival and relative freedom from prosthetic valve replacement.

Adult↗
PubMed1986

Influence of the internal-mammary-artery graft on 10-year survival and other cardiac events.

We compared patients who received an internal-mammary-artery graft to the anterior descending coronary artery alone or combined with one or more saphenous-vein grafts (n = 2306) with patients who had only saphenous-vein bypass grafts (n = 3625). The 10-year actuarial survival rate among the group receiving the internal-mammary-artery graft, as compared with the group who received the vein grafts (exclusive of hospital deaths), was 93.4 percent versus 88.0 percent (P = 0.05) for those with one-vessel disease; 90.0 percent versus 79.5 percent (P less than 0.0001) for those with two-vessel disease; and 82.6 percent versus 71.0 percent (P less than 0.0001) for those with three-vessel disease. After an adjustment for demographic and clinical differences by Cox multivariate analysis, we found that patients who had only vein grafts had a 1.61 times greater risk of death throughout the 10 years, as compared with those who received an internal-mammary-artery graft. In addition, patients who received only vein grafts had 1.41 times the risk of late myocardial infarction (P less than 0.0001), 1.25 times the risk of hospitalization for cardiac events (P less than 0.0001), 2.00 times the risk of cardiac reoperation (P less than 0.0001), and 1.27 times the risk of all late cardiac events (P less than 0.0001), as compared with patients who received internal-mammary-artery grafts. Internal-mammary-artery grafting for lesions of the anterior descending coronary artery is preferable whenever indicated and technically feasible.

Coronary Artery Bypass↗
PubMed1986

Verification of Fourier phase and amplitude values from simulated heart motion using a hydrodynamic cardiac model.

Using pusher-plate-type artificial hearts, changes in the degree of synchrony and stroke volume were compared to phase and amplitude calculations from the first Fourier component of individual-pixel time-activity curves generated from gated radionuclide images (RNA) of these hearts. In addition, the ability of Fourier analysis to quantify paradoxical volume shifts was tested using a ventricular aneurysm model by which the Fourier amplitude was correlated to known increments of paradoxical volume. Predetermined phase-angle differences (incremental increases in asynchrony) and the mean phase-angle difference calculated from RNAs showed an agreement of -7 degrees +/- 4.4 degrees (mean +/- SD). A strong correlation was noted between stroke volume and Fourier amplitude (r = 0.98; P less than 0.0001) as well as between the paradoxical volume accepted by the 'aneurysm' and the Fourier amplitude (r = 0.97; P less than 0.0001). The degree of asynchrony and changes in stroke volume were accurately reflected by the Fourier phase and amplitude values, respectively. In the specific case of ventricular aneurysms, the data demonstrate that using this method, the paradoxically moving areas may be localized, and the expansile volume within these regions can be quantified.

Fourier Analysis↗