Biomedical subjects
Publications and source records attributed to Y Leclerc.
A new bioadhesive (BioGlue, Cryolife Inc, Kennesaw, GA) was recently introduced for surgical use in thoracic aortic surgical repair. We describe our early experience and our suggested method of repair.
BACKGROUND: Postoperative oxygen consumption (VO2) is critical during the recovery period that follows open heart surgery and depends on patient characteristics and surgical factors. OBJECTIVE: To explore the surgical and patient-related factors that may influence VO2 during the early postoperative period. DESIGN: Prospective study. SETTING: Postoperative intensive care unit. PATIENTS: Study participants were 50 consecutive patients undergoing elective open heart surgery. There were 39 men and 11 women, with a mean age of 58+/-10 years. MEASUREMENTS AND MAIN RESULTS: VO2, oxygen extraction and arterial lactate were measured 1, 4, 12 and 24 h postoperatively. VO2 increased significantly during the first 12 h and stabilized thereafter. Oxygen extraction remained stable through the first 24 h. Covariance analysis on repeated measures showed that the extracorporeal circulatory period (P<0.01), age (P<0.01), body temperature (P<0.05) and use of noradrenalin (P<0.05) were predictive factors influencing postoperative VO2. Although arterial lactate increased significantly during the first 12 h period, no correlation with VO2 was found. However, covariance analysis showed that female sex, patient age (older than 65 years) and bypass period were positive correlating factors for the increase in arterial lactate. CONCLUSIONS: Patient VO2 need is decreased early after open heart surgery and returns to normal after 12 h. Surgical and patient-specific factors are responsible for these changes. Arterial lactate measurements were not found to be reliable indexes of VO2 need during this period.
We report a case of severe aortic regurgitation occurring immediately after the insertion of a mitral annuloplasty ring. On transesophageal echocardiography, regurgitation was found to originate from the retracted left coronary cusp. On direct examination, part of the aortic wall was folded, but no suture could be identified. It was reasoned that tension created by the ring caused the retraction. The problem was corrected by releasing three sutures on the ring. Postoperative course was uneventful.
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OBJECTIVE: To decrease health costs and morbidity related to extracorporeal circulation, surgeons have modified the coronary artery bypass (CAB) technique so that it can be completed without the use of extracorporeal circulation. This study summarizes initial experience with direct coronary artery revascularization on the beating heart using a coronary stabilizer. DESIGN: A case series. SETTING: The Montreal Heart Institute, a university-affiliated centre, specializing in the treatment of cardiac illnesses. PATIENTS: Ten patients underwent CAB by this technique. They presented with double or triple coronary artery disease with no intramyocardial, heavily calcified, diffused atheromatous coronary vessels, or left main coronary disease. INTERVENTION: CAB grafting in the beating heart. The anterior wall was grafted in all patients, the inferior wall in 7 and the posterior wall in 7. MAIN OUTCOME MEASURES: Patient survival and graft patency. RESULTS: One patient died of multiple organ failure not related to the grafting technique itself, and 1 patient suffered a non-Q myocardial infarction. Early coronary angiography performed on 8 patients showed 100% graft patency, most with excellent distal runoff (21/22 grafts). CONCLUSION: In patients with adequate anatomy, performance of CAB without extracorporeal circulation can achieve excellent early results provided there is appropriate mechanical stabilization of the beating heart.
OBJECTIVES: To evaluate the value of concomitant coronary endarterectomy (CE) in the modern era of coronary revascularization. METHODS: Retrospective study. Twenty-eight patients (five women; 23 men) who underwent coronary endarterectomy were angiographically studied 24 +/- 22 months after the procedure. Necessity CE (vessel completely occluded or with lumen less than 1 mm) was performed on the left anterior descending (LAD) artery in 12 patients, the right coronary artery (RCA) in nine, the obtuse marginal artery (OM) in five and a diagonal branch in two patients. Conduits used for revascularization were the internal thoracic artery (ITA) in 11 (all anastomosed to the LAD; combined with saphenous vein patch in four) and a saphenous vein graft in 17 patients. Mean atherosclerotic core length was 3.3 +/- 1.8 cm. An average of 3.1 +/- 0.7 distal anastomoses per patient were constructed, with mean aortic cross-clamp and cardiopulmonary bypass times of 61.2 +/- 20.2 mins and 94.0 +/- 23.5 mins, respectively. RESULTS: Overall, angiographic patency rate was 71% (20 of 28) for the endarterectomized vessels (12 of 12 LAD, six of nine RCA, two of five OM and none of two diagonal arteries) and 93% (57 of 61) for the nonendarterectomized vessels. Among the eight patients with occluded CE vessels, two sustained a perioperative myocardial infarction, five developed angina during follow-up, and one patient remained asymptomatic. CONCLUSION: Necessity CE demonstrates acceptable mid-term patency. In addition, this study showed excellent patency following CE of the LAD revascularized with the ITA, with or without only a saphenous vein patch.
Single-stage replacement of the ascending, transverse and descending thoracic aorta remains a noteworthy surgical intervention associated with significant morbidity. Aside from the surgical aspects, brain preservation during the circulatory arrest period, which is generally needed to perform the procedure, is a constant preoccupation for the surgeon. A 43-year-old man had an extensive thoracic aneurysm 4 years after an initial type A aortic dissection involving the entire thoracic aorta. The Cooley technique of retrograde replacement of the thoracic aorta was performed along with retrograde cerebral perfusion. The combined sternal and thoracic approach suggested for this technique provided excellent exposure and, despite a circulatory arrest time of 88 minutes, the patient's cognitive abilities were found to be well preserved at follow-up 2 months after the surgery, indicating the efficacy of the cerebral retrograde perfusion. The authors conclude that retrograde replacement of the thoracic aorta combined with cerebral retrograde perfusion are convenient procedures that allow extensive aortic replacement without brain damage.
OBJECTIVES: The purpose of this study was to determine the impact of changes in flow on aortic valve area (AVA) as measured by the Gorlin formula and transesophageal echocardiographic (TEE) planimetry. BACKGROUND: The meaning of flow-related changes in AVA calculations using the Gorlin formula in patients with aortic stenosis remains controversial. It has been suggested that flow dependence of the calculated area could be due to a true widening of the orifice as flow increases or to a disproportionate flow dependence of the formula itself. Alternatively, anatomic AVA can be measured by direct planimetry of the valve orifice with TEE. METHODS: Simultaneous measurement of the planimetered and Gorlin valve area was performed intraoperatively under different hemodynamic conditions in 11 patients. Left ventricular and ascending aortic pressures were measured simultaneously after transventricular and aortic punctures. Changes in flow were induced by dobutamine infusion. Using multiplane TEE, AVA was planimetered at the level of the leaflet tips in the short-axis view. RESULTS: Overall, cardiac output, stroke volume and transvalvular volume flow rate ranged from 2.5 to 7.3 liters/min, from 43 to 86 ml and from 102 to 306 ml/min, respectively. During dobutamine infusion, cardiac-output increased by 42% and mean aortic valve gradient by 54%. When minimal flow was compared with maximal flow, the Gorlin area varied from (mean +/- SD) 0.44 +/- 0.12 to 0.60 +/- 0.14 cm2 (p < 0.005). The mean change in Gorlin area under different flow rates was 36 +/- 32%. Despite these changes, there was no significant change in the planimetered area when minimal flow was compared with maximal flow. The mean difference in planimetered area under different flow rates was 0.002 +/- 0.01 cm2 (p = 0.86). CONCLUSIONS: By simultaneous determination of Gorlin formula and TEE planimetry valve areas, we showed that acute changes in transvalvular volume flow substantially altered valve area calculated by the Gorlin formula but did not result in significant alterations of the anatomic valve area in aortic stenosis. These results suggest that the flow-related variation in the Gorlin AVA is due to a disproportionate flow dependence of the formula itself and not a true change in valve area.
Perivalvular leaks following prosthetic valve replacement are associated with significant morbidity. Management has classically consisted of valve replacement or blind surgical repair. Our study examines the results of intraoperative transesophageal echo-guided repair of perivalvular leaks (ITEGR). Between November 24, 1987 and January 1st, 1996, 23 patients (10 men, 13 women) at the Montreal Heart Institute underwent ITEGR. Ninety percent were NYHA class III-IV preoperatively. Seventy to 85% had significant cardiac insufficiency preoperatively. Eighty-six percent of the leaks were in the mitral valve location, 90% of which were mechanic prosthesis. Eighty-nine percent of patients had hemolysis with an average LDH of 720. Mean bypass time was 125 minutes with a mean clamp time of 77 minutes. Most patients were undergoing a third operation at the time of repair. Operative mortality was 8%, all due to biventricular failure. A mean follow-up of 67 months showed a late death of 10%. Of the 19 survivors, 77% were NYHA class I-II. Overall mortality was 20%. In our institution valve re-replacement in similar circumstances was associated with an operative and long-term mortality of 7% and 26% respectively. We conclude that intraoperative transesophageal echo-guided repair is an excellent management alternative in patients with perivalvular leaks with decreased late and overall mortality.
Surgical management of the carotid disease remains controversial in patients affected with coronary artery atheromatous disease. We report the Montreal Heart Institute experience on the influence of carotid disease on postoperative neurologic events of 501 consecutive patients operated on for coronary revascularization during the period from January 1994 to December 1994. There were 381 men and 114 women averaging 62 +/- 9 years old. Major risk factors were high blood pressure (35%), and smoking habit (48%). Fifty-nine patients presented clinical signs of carotid atheromatosis and among them 21 had significant carotid stenosis (> 80% decrease of cross sectional area). During surgery, the mean duration of extracorporeal circulation (ECC) was 76 +/- 31 minutes and the mean perfusion pressure (MPP) was 70 +/- 11 mmHg. The use of inotropic drugs was mandatory in 26% of the cases and the mean arterial lactate (AL) dosage during ECG was 3.07 +/- 1.35 mM/L. During the perioperative period, 13 (2.5%) patients sustained neurologic disturbances of which 5 (1%) were lateralized. Among them, 8 completely recovered whereas 3 of the 5 with permanent damage died. None of the patients with preoperative stigmata of carotid disease experienced lateralized neurologic deficit. Multivariate regression analysis identified the use of vasopressor drugs and perioperative increase of AL as predictive factors. We conclude that in our series, the incidence of neurologic complications was low. The presence of carotid atheromatosis did not increase the postsurgical risk of cerebrovascular accident, however, the increased incidence of neurologic events associated with inotropic drugs and increased AL suggests a direct link with a systemic oxygen debt. Consequently, we do no recommend concurrent prophylactic surgery during coronary artery revascularization.
OBJECTIVES: To evaluate the short-term result of the coronary artery revascularization without cardiopulmonary bypass for triple vessel disease, including the circumflex territory performed on the stabilized beating heart. METHODS: Prospective study conducted on the first 35 consecutive patients with triple vessel disease operated upon without cardiopulmonary bypass by a single surgeon (RC) at the Montreal Heart Institute between October 1996 and March 1997. RESULTS: Mean age of patients was 64 +/-1.6 years and the majority were men (30). Most common risk factors were hypercholesterolemia (65%) and familial history (55%) of ischemic heart disease. Main surgical indication was unstable angina (74%) and mean preoperative left ventricular ejection fraction was 53 +/- 3%. Hundred and twelve bypass were constructed averaging 3.2 +/- 0.1 grafts/patients of which 39 were made on branches of the circumflex artery. Average ischemic time was 34.17 +/- 2.17 minutes. The internal thoracic artery, saphenous vein, and radial artery were used as a vascular conduit in 44, 67, and 1 occasions respectively. There was one operative mortality, and one non Q perioperative myocardial infarction (CK-MB: 89 U/L). No patient required aortic counterpulsation balloon assistance. The average postoperative CK-MB (U/L) were 12.2 +/- 1.9, 15.2 +/- 3.2, and 10.3 +/- 1.7 at 1, 24 and 48 hours respectively. During the post-operative period 26% (9) of the patients presented atrial fibrillation, 6.5% (2) early reexploration for bleeding, and 63% (22) did not require transfusion. Average stay in hospital was 6.1 +/- 45 days. Coronary grafts were angiographically assessed in the first 10 patients and at the postmortem exam in one and displayed a 100% patency with 93.5% (29/31) adequate runoff. CONCLUSION: Triple vessel coronary artery disease revascularization is feasible on the beating heart without cardiopulmonary bypass with excellent short-term clinical and angiographic results.
BACKGROUND: A prospective, randomized clinical study involving 34 patients undergoing heart transplantation compared myocardial preservation of donor hearts maintained with continuous reperfusion with retrograde warm blood cardioplegia during surgical implantation versus the standard cold topical irrigation. METHODS: Hearts in both groups were arrested with a standard crystalloid solution and maintained in a cold saline solution during transportation. In the retrograde group, cardioplegia was administered through a catheter in the coronary sinus during surgical implantation. An average of 471 +/- 30 mL of hyperkalemic crystalloid solution diluted 1:4 in warm blood from the oxygenator was infused. In the standard group, the heart was kept cold by topical irrigation of cold saline solution and was reperfused only when the ascending aorta was unclamped. RESULTS: Preoperative characteristics of donors and recipients were similar in the two cohorts. Ischemic time average 139 +/- 12 minutes in the retrograde group compared with 130 +/- 11 minutes in the standard group (p = 0.57). Cardiopulmonary bypass time averaged 89 +/- 4 minutes in the retrograde group and 110 +/- 12 minutes in the standard group (p = 0.12). Defibrillation at reperfusion was performed in 4 patients (4/17, 24%) in the retrograde group and 12 patients (12/18, 67%) in the standard group (p = 0.01). There were no deaths in the retrograde group (0/17), whereas in the standard group, 3 patients (3/17) died of early graft failure (p = 0.11). Four early graft failures occurred in the standard group (p = 0.06). Two patients (2/17, 12%) were weaned from bypass with ventricular assist devices in the standard group. The number of subendocardial necrotic cells in the first two weekly endomyocardial biopsy specimens averaged 2.7 +/- 0.8 cells/mm2 in the retrograde group and 5.9 +/- 2.4 cells/mm2 in the standard group (p = 0.12). CONCLUSIONS: Retrograde warm blood reperfusion appears to improve the initial recovery of transplanted hearts. The technique is easy to use and may be a useful approach to graft protection during surgical implantation.
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Surgeons have limited ability to evaluate intraoperatively the patency of internal thoracic artery graft as a bypass for coronary artery revascularization. We used continuous-wave Doppler ultrasonography to study the velocity of the internal thoracic artery before harvesting and after grafting (scanning probe, 8 MHz). Systolic and diastolic frequency shift (in kilohertz) and systolic frequency/diastolic frequency index were analyzed. Twenty four internal thoracic artery grafts in 15 patients were studied. Fourteen internal thoracic artery grafts were anastomosed to the left anterior descending artery, one to a diagonal artery, and nine to the circumflex artery. The mean systolic frequency before harvesting was 1.19 +/- 0.40 KHz and no significant differences were found between the right and the left internal thoracic artery (right, 1.17 +/- 0.37; left, 1.19 +/- 0.42 KHz). There was a 40% drop in systolic frequency related to the harvesting. Mean systolic frequency decreased after grafting (1.19 +/- 0.40 versus 0.87 +/- 0.32 KHz; p < 0.01) whereas mean diastolic frequency doubled (0.32 +/- 0.12 versus 0.83 +/- 0.4 KHz; p < 0.001) and mean diastolic frequency/systolic frequency index increased from 28% +/- 11% to 101% +/- 39% (p < 0.001), indicating an increased myocardial vascularization during diastole. No significant difference was found between grafted arteries (left anterior descending versus circumflex). All patients had an uneventful postoperative course and no perioperative myocardial infarction was reported. Doppler flow quantification of internal thoracic artery bypasses may give the surgeon an opportunity to evaluate intraoperatively the physiologic features and patency of the internal thoracic artery before and after coronary artery bypasses.
Long term results of tricuspid valve replacement, were evaluated by echocardiographic and clinical means retrospectively on 55 patients hospitalized at the Montreal Heart Institute between 1969 and 1993. Twenty seven percent were male and 73% female. Taking into account differences in means of myocardial protection the whole population was divided in 2 groups. Group 1: 19 patients from 1969 to 1980. Group 2: 36 patients - from 1981 to 1994. Forty seven patients (85%) received a bioprosthesis and 8 (15%) a mechanical valve. Forty one (74%) had another surgical procedure and 60% (33 patients) were re-operations. Mortality at 30 days is 23% (13 patients) -15% group 1 and 27% group 2. Twenty six patients (72%) of group 2 were re-operations compared with 7 (36%) for group 1 (p = 0.026). Risk factors of operative mortality were: high systolic pulmonary pressure (0.051), bypass time (0.012) and abnormal ejection fraction (0.025). Mean time of follow up is 113.8 months completed at 95%. Six patients were re-operated; 4 for failure of bioprosthesis 11.5 years (mean) after initial surgery. Forty three percent of patients presented with an amelioration of NYHA class. 26% in class I and 50% in class II. Mean gradient across the tricuspid valve was 4.1 +/- 1 mm Hg. Twenty two over 42 patients (50%) died during follow up: 75 months after surgery.
The surgical cohort of the Bypass Angioplasty Revascularization Investigation (BARI) is the largest group of patients with multivessel coronary artery disease randomly assigned to surgical treatment. This report presents baseline and operative characteristics of the cohort and describes some aspects of the variability in surgical practice among the 14 primary clinical centers and 4 co-investigational sites participating in BARI. Preoperative clinical and angiographic data and intraoperative variables were reviewed in 892 patients who were randomly assigned to coronary artery bypass grafting (CABG) and underwent operation. Associations between patient/lesion variables and operative characteristics are described. Of patients assigned to CABG, 87% underwent an operation within 2 weeks of randomization, as recommended in the protocol. Mean age of the 892 patients was 61 years, and mean age of the 235 women was greater than that of men (64 years vs 60 years); 64% of the surgical patients were classified as having unstable angina during the 6 weeks prior to randomization. Coronary angiography demonstrated 3-vessel disease (50% diameter narrowing by caliper measurement) in 41% of patients, and disease of the left anterior descending coronary artery was present in 87% of patients. A mean of 3.1 coronary arteries per patient were bypassed, and 82% of patients received 1 (70%) or 2 (12%) internal thoracic artery grafts. Prevalence of internal thoracic grafts was lower in elderly patients (74% of patients > or = 70 years), in women (72% vs 85% in men; p < 0.01), and in black participants (65%).(ABSTRACT TRUNCATED AT 250 WORDS)
Carpentier-Edwards pericardial bioprostheses were implanted in 600 patients: 416 aortic valve replacement, 115 mitral valve replacement, 6 isolated tricuspid, and 63 multiple valve replacements. The survival rates were 70% at 10 years after aortic valve replacement, 62% 8 years after mitral valve replacement, and 57% at 8 years with multiple valve replacement. Overall, 69 patients suffered one or more valve-related complications. The 10-year freedom rates from embolism were 91% (aortic valve replacement), 92% (mitral valve replacement), and 89% (multiple valve replacement), and those from endocarditis were 95%, 93%, and 85%, respectively. In 18 of the 35 patients, reoperation was due to primary valve dysfunction. Freedom from primary dysfunction was 87% at 10 years with aortic valve replacement, and at 8 years, it was 79% with mitral valve replacement and 77% with multiple valve replacement. A direct correlation was found between freedom from valve dysfunction and age of the patient at operation, with a 10-year-free rate of 90% among patients older than 59 years. This bioprosthesis has an excellent durability up to 10 years in the aortic position. More data regarding its long-term durability in the mitral position are needed. It is currently our valve substitute of choice when a bioprosthesis is indicated.
The purpose of this study was to describe the mechanism and determine predictive factors of mitral valve rupture requiring valve replacement following percutaneous mitral commissurotomy. Of the 350 consecutive patients treated by balloon mitral commissurotomy, the procedure was not completed in 16, and 11 developed acute severe mitral regurgitation requiring valve replacement: seven cases of anterior leaflet rupture, three cases of posterior leaflet rupture and one case of anterior chordal surface. These 27 group I patients were compared to the remaining 323 (group II) in whom the procedure was completed. The 11 excised valves were evaluated by an experienced pathologist. Eight of the 11 patients had an echocardiographic score < 8 (mean score 6.5 +/- 1), no valvular calcification at X-ray and double balloon percutaneous mitral commissurotomy. Microscopy in six patients showed focal fibrous thickening at the site of the rupture but no calcification. One patient developed severe mitral regurgitation due to chordal rupture with an Inoue balloon. The two remaining patients had an echo score of ten and valve calcification on X-ray. Microscopy revealed severe homogeneous chronic rheumatic mitral disease. In one of these two patients, leaflet rupture was related to an 'oversized balloon' (2 x 19 mm + 15 mm). Statistical analysis showed only echo score differences between the two groups (6.9 +/- 1.4 in group I vs 8.2 +/- 1.6 in group II, P < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)