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Biomedical subjects

L C Pelletier

Publications and source records attributed to L C Pelletier.

At least 127 records · Page 7Linked to original sources

Early and late prognosis after reoperation for prosthetic valve replacement.

From 1969 to 1983, 89 patients underwent replacement of a prosthetic heart valve, an average of 66 months after initial implantation, because of primary failure of the prosthesis in 39 patients (44%), endocarditis in 16 (18%), systemic valve-related complications in 16 (18%), and periprosthetic leaks in 13 (15%). In the remaining five patients (5%), a prosthesis was removed concomitantly with the replacement of another native heart valve. A mechanical valve was replaced in 64 cases (72%) and a bioprosthesis in 25 (28%). Forty-six of the prostheses (52%) were in the mitral position, 37 (42%) were in the aortic position, and six patients (6%) underwent replacement of two prostheses. Preoperatively, four patients were in Functional Class I, 21 in Class II, 37 in Class III, and 27 in Class IV. There were 19 early deaths (21.3%). Early mortality was significantly higher with aortic (35.1%) than with mitral prosthetic valve replacement (8.7%, p less than 0.01). Preoperative diagnosis had a significant correlation with mortality, which was higher with infective endocarditis (62.5%) than with all other indications for operation (12.3%, p less than 0.001). No correlation was found with the preoperative clinical class of the patients. During the time period of this study, there was a marked decline in the mortality rate, which decreased from 29.2% prior to 1979 to 7.4% during the last 2 years (p less than 0.05). Actuarial survival was 60% at 5 years and 38% at 10 years after reoperation. Among the 53 survivors followed up for an average of 39 months, 47 (88.9%) remained in Class I or II and six were in Class III (11.3%) at last follow-up. A second prosthetic valve replacement (third valve replacement) was required in eight patients, three of whom died at re-replacement. Recent improvements in myocardial protection techniques, in the treatment of prosthetic valve endocarditis, and increased surgical experience have contributed to decrease the risk of reoperation for prosthetic valve replacement. Late results are similar to those of a first valve implantation.

Actuarial Analysis↗

Early valve replacement in active infective endocarditis.

Infective endocarditis is associated with a high mortality, but previous studies have suggested that the major complications of the condition might be prevented by early surgery. Of 50 patients treated for infective endocarditis at the Montreal Heart Institute from 1977 to 1982, 30 were treated nonsurgically and the remaining 20 underwent early valve replacement before preoperative antibiotic therapy was completed. Of these 20, 14 had native valve endocarditis and 6 prosthetic valve endocarditis. The organisms involved were Streptococcus sp in 11, Staphylococcus aureus in 2, gram-negative organisms in 3 and Candida parapsilosis in 1. Blood cultures remained negative in three patients. There were three early deaths (15%) following operation and one late death (5%). Infection on implanted prostheses did not recur, but reoperation was required in one patient because of prosthetic dehiscence 7 months after initial implantation. All resected valves displayed evidence of infection. Follow-up was obtained in all survivors. After an average follow-up of 26 months, 12 patients remained in functional class I and 4 in class II (New York Heart Association classification). Early valve replacement has resulted in improved survival of patients with infective endocarditis and is now associated with a low operative mortality and morbidity.

Adolescent↗

Open-heart surgery in elderly patients.

Between March 1975 and March 1980, 50 patients aged 70 to 78 years underwent open-heart surgery at the Montreal Heart Institute. Coronary bypass was performed in 23 patients, valve replacement in 16 and combined coronary and valve surgery in 11. There were four early deaths, all due to cardiac causes. Early postoperative complications occurred in 58% of the patients. There were seven late deaths, five in the valve replacement groups and two in the isolated coronary bypass group. The cumulative survival rate 5 years after surgery was estimated at 76%. While 82% of the survivors were in functional class III or IV before surgery, 90% were in class I or II when last seen, after an average postoperative follow-up of 3 years. Nonfatal late complications occurred in eight of the survivors, one of whom suffered a major hemorrhage due to anticoagulant therapy. Thus, open-heart operations can be offered to the elderly, with a low risk of operative death. The late clinical improvement, with a return to a normal lifestyle, justifies a surgical approach for patients in otherwise good general condition.

Aged↗

[Endocarditis caused by Candida parapsilosis (para-krusei)].

This paper describes a case of Candida Parapsilosis endocarditis in a patient with a mitral valve prosthesis implanted two years previously. This history started with a cerebrovascular accident associated with pyrexia. A complex medico-surgical therapeutic approach controlled the infection. This consisted of systemic and local (immersion of the prosthesis) antifungal therapy, bathing the left heart chambers in 5 p. 100 iodine solution and two valve replacements at 8 months intervals. The second surgery was not related to recurrence of the candida infection but to a perivalvular leak attributed to the insertion of the prosthesis into tissues inflamed by recent infection. Despite the improvement in the prognosis of fungal infection due to an early surgical approach, it is still essential to try and prevent the disease, the mortality rate still being over 80 p. 100. It is essential to be very careful when using intravenous catheters and aerosols; the indications of antibiotherapy must also be respected.

Candidiasis↗

Diagnostic criteria and prognosis of perioperative myocardial infarction following coronary bypass.

To evaluate the incidence of perioperative myocardial infarction (PMI), serial determinations of serum creatine kinase isoenzymes (CK-MB), electrocardiograms (ECGs), and pyrophosphate myocardial scans were performed in 112 patients undergoing isolated coronary bypass grafting. An abnormal increase in total CK-MB liberation (Q greater than 9.8 IU ml-1 kg) occurred in 25 patients (22.3%), new Q waves were present at ECG in 10 patients (8.9%), and the pyrophosphate myocardial scan was abnormal in 13 patients (11.6%). All tests were negative in 81 patients (72.3%). A diagnosis of PMI was established if confirmed by at least two of the techniques; this diagnosis was made in 15 patients (13.4%). The pattern of CK-MB liberation in patients with a PMI, characterized by a high peak and a prolonged release, was significantly different from that of patients without a PMI. The most important predictive factor for PMI was the duration of myocardial ischemia during the operation. Patients who had a PMI had more frequent early complications, and their prognosis at 2 years showed a 51% probability of remaining free of new cardiac events as compared to 96% for the group of patients without a PMI (p less than 0.001). PMI is not a benign complication of coronary bypass, and its detection appears improved by a combination of diagnostic tests.

Adult↗

Outpatient management of intercostal tube drainage in spontaneous pneumothorax.

In a series of 226 patients with spontaneous pneumothorax, 167 (74%) were managed successfully on an outpatient basis by observation (20%) or by intercostal tube drainage and a flutter valve (54%). Only 59 patients (26%) were hospitalized, and 42 of these were treated surgically (18.6%). Outpatient management with a flutter valve has proved to be safe, efficient, and economical.

Adolescent↗

[Unusual traumatic rupture of the thoracic aorta with avulsion of the left subclavian artery].

Of the many cases of traumatic rupture of the aorta diagnosed each year at l"Hôpital du Sacré-Coeur, Montreal, most patients are already in irreversible shock when seen. However, during the period Oct. 1, 1974 to Sept. 30, 1975, prompt surgical treatment saved six patients. One of these six patients had a complete trans-section of the aortic arch between the left carotid and left subclavian arteries with avulsion and slight retraction of the left subclavian artery. Repair of the aortic arch and left subclavian artery was accomplished without extracorporeal circulation. A sutureless temporary bypass shunt was created by (a) cannulating the ascending and descending aorta, the cannulas being secured with purse-string sutures and joined by a 3/8-inch (94-mm) polyvinyl chloride (PVC) tube connected to a "double T" adapter, and (b) joining two small PVC tubes from the adapter with two straight cannulas, a no. 14 being inserted into the innominate artery and a no. 12 being inserted into the left carotid artery. With this temporary bypass created, the ascending and descending aorta and aortic arch vessels were all clamped. Aortic continuity was re-established with a tubular Dacron graft (diameter, 19 mm) to which was anastomosed a side-arm of knitted Dacron (diameter, 10 mm) to repair the left subclavian artery. Throughout the temporary perfusion the brain, spinal cord and all abdominal viscera were well protected. No sign of ventricular distension was detected. This report is the first in which complete transsection of the aortic arch has been managed by a sutureless bypass shunt allowing perfusion of all aortic arch vessels without extracorporeal circulation.

Adult↗

Spontaneous pneumothorax: outpatient management with intercostal tube drainage.

In a series of 104 episodes of pneumothorax 75 percent of episodes were managed successfully on an outpatient basis by observation (23.1 percent) or by intercostal tube drainage using a flutter valve (51.9 percent). The patients for whom this treatment was not successful were admitted to hospital; 17 of them (16.3 percent of 104) were treated surgically. Bleb suturing with a stapling device and dry sponge abrasion of the pleura was the operation of choice.

Adolescent↗

Control of high and low blood pressure in the dog by aortic and sinus nerves.

1. Changes in afferent activity in the aortic and sinus nerves with alterations of blood pressure were studied in anesthetized dogs. Mean aortic blood pressure was changed from 220 to 50 mmHg by using a pressurized reservoir connected to the abdominal aorta. 2. The stimulus--response curve (defined by measuring the mean impulse frequency at various pressures) from both nerves was S-shaped; the curve for the aortic nerve was shifted to the right of the sinus nerve curve. 3. In the dog, the aortic arch baroreceptors act predominantly as an anti-hypertensive mechanism; at lower pressures, the major control occurs through the sinus baroreflex.

Afferent Pathways↗

Influence of age on late results of valve replacement with porcine bioprostheses.

From 1976 to 1987, 877 patients, aged 13 to 80 years, underwent valve replacement with a Carpentier-Edwards porcine bioprosthesis--330 aortic, 421 mitral, and 126 multiple replacements. Patients were divided into 4 age groups, according to their age at the time of surgery: group I, less than 45 years (190 patients), group II, 45 to 54 years (203 patients), group III, 55 to 64 years (304), and group IV, 65 to 80 years (180 patients). Follow-up was 97.5 complete, averaged 85 months, and totalled 5624 patient-years. There were 79 early deaths (9%), and 181 late deaths. Overall survival was 80% and 64% at 5 and 10 years. Operative mortality increased significantly with age, and late survival was significantly better for group I. Intrinsic structural deterioration was the most common cause for reoperation and was responsible for 91% of the 143 reoperations. Incidence of intrinsic structural deterioration and of reoperation decreased significantly with increasing age, with respective freedom rates at 10 years of 57 and 54 in group I compared to 93 and 92% in group IV. Freedom from treatment failure (including early deaths, valve-related deaths, and valve-related complications with permanent disability) was similar for all 4 groups ranging from 78 to 85%, without any correlation with age of the patient. At last follow-up, a similar proportion of patients of each group remained asymptomatic, patients in functional class I ranging from 50 to 55%. Thus, age is a major determinant of durability of bioprostheses, but it does not appear to have a significant role in the overall success of valve replacement.

Actuarial Analysis↗