Biomedical subjects

R Cartier

Publications and source records attributed to R Cartier.

At least 55 records · Page 3Linked to original sources

PubMed1999

Early and long-term results of percutaneous transluminal angioplasty of the lower abdominal aorta.

PURPOSE: The purpose of this study was to determine the early and long-term results of percutaneous transluminal angioplasty (PTA) of atherosclerotic lower abdominal aorta stenosis. METHODS: This study was performed as a retrospective study. From 1980 to 1997, 46 patients with chronic lower limb ischemia with moderate to severe claudication as the result of isolated infrarenal disease or aortoiliac disease underwent PTA. All patients underwent angiography before and after angioplasty and Doppler ultrasound scan examination with ankle-brachial index determination. No stents were used. RESULTS: The technical success rate was 96% (44 of 46 cases). Thirty-eight patients (83%) immediately showed clinical, hemodynamic, and angiographic improvement. The initial success rate for patients with isolated infrarenal or bifurcation disease was 92%, whereas it was 71% for aortoiliac disease. Among the eight patients with no initial improvement, four had clinical deterioration and two required emergency surgical revascularization. There were no other complications. Fifty-six percent of the patient conditions (95% confidence interval [CI], 38% to 74%) remained clinically improved at the 5-year follow-up examination. Recurrence of symptoms was caused by femoropopliteal disease in most patients. The primary patency rate assumed with maintenance of hemodynamic improvements was 70% (95% CI, 52% to 88%) and 64% (95% CI, 44% to 84%) at 4 and 5 years of follow-up, respectively. The primary patency rate at 4 years for patients with isolated infrarenal or bifurcation disease was 83% (95% CI, 64% to 100%), whereas it was 55% for aortoiliac disease (95% CI, 30% to 80%; P =.06) The variables that were statistically predictive of patency failure were poor runoff (P =. 01) and presence of aortoiliac atherosclerotic disease (P =.04). CONCLUSION: Our results suggest that PTA is an excellent treatment for chronic arterial insufficiency of the lower extremities as the result of isolated atherosclerotic lower abdominal aortic occlusive lesions because of good long-term patency. Aortic PTA for those patients with iliac involvement or with poor runoff gives acceptable results but carries lower patency and clinical success rates.

Adult↗

PubMed1999

Early versus late extubation after coronary artery bypass grafting: effects on cognitive function.

OBJECTIVE: To compare the effects of a short period of mechanical ventilation and sedation and a longer one on cognitive functioning of patients exposed to cardiopulmonary bypass (CPB). DESIGN: A randomized, prospective study. SETTING: Tertiary-care university hospital. PARTICIPANTS: Forty-eight adult patients with surgical coronary artery disease. INTERVENTION: Elective coronary artery bypass surgery. MEASUREMENT AND MAIN RESULTS: Patients (n = 48; mean age, 60.12+/-9.30 years) were randomized to either group I (mean delay, 3.49+/-2.21 hours) or group II (mean delay, 10.32+/-1.75 hours). Cognitive functioning was evaluated before surgery, postoperatively, and at the 8-week follow-up. Tests included measures of central nervous system integrity, attention/concentration and psychomotor performance, verbal fluency, visual scanning speed, mental flexibility, auditory and visual attention, and verbal memory. Covariance analyses were used for group comparisons. Covariates were age, education, and baseline or postoperative performance. No differences in cognitive functioning were found between the two groups. Globally, performance deteriorated for 34.1% of the patients at the posttest evaluation, whereas 2.3% improved and 63.6% remained unchanged. At follow-up, nearly 40.5% of the patients showed an improvement from baseline, 2.4% still had deficits, and 57.1% had no change. None of the cognitive functions appeared to be more affected than others. CONCLUSION: Early extubation and a shortened period of anesthesia/analgesia do not appear to positively or negatively affect cognitive functioning at 3 to 5 days and 8 weeks postoperatively. Early extubation is suggested because it has no deleterious effect (besides the low risk for reintubation) and it may facilitate patients' care in the intensive care unit.

Adult↗

PubMed1999

Characterization of the natural history of cervical heterotopic heart transplantation with echocardiography.

BACKGROUND: Limitations of the dog model of orthotopic heart transplantation to study rejection include the need for extracorporeal circulation and transfusions. Heterotopic cervical heart transplantation may improve on these limitations. It is not known whether the natural history after heterotopic transplant is similar to that after orthotopic grafting. METHODS: Twenty-one dogs underwent cervical heterotopic heart transplantation. Serial echocardiographic studies were performed 1 to 3 hours after surgery, at 24 hours, 48 hours later, and immediately before killing (5 to 7 days). RESULTS: LV diastolic and systolic areas were elevated immediately after transplantation (4.95+/- 1.49 cm2 and 3.36+/-1.18 cm2 respectively) but decreased at 24 hours (3.93+/-1.20 cm2, p = 0.0003 and 2.44+/-0.96 cm2, p = 0.16). Thereafter, a progressive increase in LV diastolic and systolic areas was observed until sacrifice (5.53+/-2.20 cm2 and 4.59 +/-2.14 cm2, p < 0.001 vs 24 hours). LV fractional area shortening (FAS) and fractional volume change were depressed immediately after transplantation (28.2+/- 12.8% and 40.4+/-12.3%, respectively), but increased at 24 hours (35.7+/-10.0%,p = 0.11 and 50.3+/-4.0%,p = 0.02). FAS decreased at 48 hours to 19.6+/-11.1% (p = 0.01 vs 24 hours). The centractility indexes were markedly reduced before killing (FAS = 14.0+/-8.2% and LVEF = 18.4+/-1.3%, p < 0.0005 vs 24 hours). The thickness of the interventricular septum increased from 11.9+/-2.0 mm at baseline to 14.4+/-4.2 mm before sacrifice (p = 0.007). CONCLUSION: The evolution of dogs after heterotopic cervical heart transplant is comparable to that after the more standard orthotopic graft. Considering its multiple practical advantages including the easy echocardiographic follow-up, heterotopic transplantation may become a very practical model to use for the study of rejection after heart transplantation.

Animals↗

PubMed1999

Polycation-mediated transfection: how to overcome undesirable side effects of sticky DNA complexes.

Using polycationic transfection one encounters undesired persistent binding to cells of sticky polycation/DNA complexes. These complexes simulate transfection under conditions where no uptake is expected e.g. at 4 degrees C if the uptake is by endocytosis. To overcome this problem, using H1/DNA complexes, we developed an easy and nontoxic method for removing the sticky complexes not taken up during the transfection phase. The cells are simply washed with isotonic (0.1 M) MgCl2 solution, which enables the complete removal of the complexes by their rapid dissolution.

Cell Line↗

PubMed1999

Post-traumatic thoracic pseudoaneurysm repair with an endoluminal expandable stent.

Recent technological improvement has allowed endoluminal correction of thoracic and abdominal aortic aneurysm through percutaneous insertion of expandable stents. A woman who presented with chronic pseudoaneurysm of the thoracic aorta 10 years after being in a car accident is presented. A Talent stent was introduced through the femoral artery and successfully deployed under fluoroscopic guidance across the aneurysmal defect. Recovery was uneventful, and 12 months later the patient remained asymptomatic.

Accidents, Traffic↗

PubMed1999

Beating heart coronary artery bypass grafting: technical aspects and results in 200 patients.

OBJECTIVE: To describe the initial experience of the first 200 patients who underwent coronary artery bypass grafting (CABG) on beating hearts at the Montreal Heart Institute, Montreal. DESIGN: A prospective cohort of 200 patients was analyzed to study immediate and short term (two-year follow-up) results. SETTING: Patients underwent CABG at the Montreal Heart Institute from February 1996 to June 1998. The first 30 patients underwent CABG without the use of a myocardial wall stabilizer (group 1), and a myocardial wall stabilizer was used in the following 170 patients (group 2). PATIENTS: Group 1 patients averaged 60+/-10 years of age compared with 66+/-10 years in group 2 (P=0.002). Twelve patients (40%) in group 1 had unstable angina compared with 107 patients (63%) in group 2 (P=0.03). INTERVENTIONS: Group 1 patients underwent 1.7+/-0.7 CABG per patient compared with 2.4+/-0.8 grafts per patient in group 2 (P=0.001). Sixty-seven patients (39%) in group 2 had an obtuse marginal coronary artery grafted, and 145 patients (73%) of both groups had a complete myocardial revascularization. RESULTS: Ten patients (5%) in both groups were converted to cardiopulmonary bypass during surgery. Seven patients (3.5%) died postoperatively: five from myocardial infarction, one from aortic dissection and rupture, and one from arrhythmia. Seventeen patients (8.5%) suffered a perioperative myocardial infarction. In groups 1 and 2, respectively, actuarial survival was 100% and 95+/-2%, and freedom rate from reoperation, percutaneous balloon dilation and recurrent myocardial infarction averaged 93+/-4% and 97+/-2% 18 months following CABG. CONCLUSION: CABG on beating hearts appears to be an alternative approach to the use of cardiopulmonary bypass in selected patients.

Aged↗

PubMed1999

[Systemic coronary surgery in the beating heart. Experience in 250 cases].

OBJECT: To report our recent experience with off-pump coronary artery revascularization in multi-vessel disease. METHODS: Between October 1996 and August 1998, 250 off-pump (OP) procedures were completed at the Montreal Heart Institute, representing more than 90% of all procedures done during the same time frame (97% for 1998). These patients have been compared to 1870 patients operated upon under cardiopulmonary bypass during the years 1995-1996 (CPB). RESULTS: Mean age, sexe distribution, and preoperative risk factors were comparable for both groups. On average 2.89 +/- 0.8 and 2.84 +/- 0.6 grafts/patient were completed in OP and CPB groups respectively. A majority (70%) of patients had either a triple or quadruple bypass. Coronary anastomoses were achieved with myocardial mechanical stabilization and heart "verticalization". Ischemic time was shorter in the OP group (29.8 +/- 0.9 vs 45 +/- 0.4 min, p < 0.05). Similarly, need for transfusion was significantly less (OP: 34 vs CPB: 66%, p < 0.005). Use of postoperative intra-aortic counterpulsation as well as the raise of CK-MB were lesser in the OP group. Operative mortality (OP: 1.6%, vs CPB: 2%, p = ns) and perioperative myocardial infarction rate (OP: 3.6% vs CPB: 4.2) were comparable for both groups. CONCLUSION: Off-pump complete coronary artery revascularization is an acceptable alternative to conventional surgery in a majority of patients with good results given progressive experience, rigorous technique, and adequate coronary artery stabilization.

Aged↗

PubMed1999

[Left main coronary artery stenosis and revascularization in the beating heart. Short- and long-term experience].

OBJECT: To determine the safety of surgical revascularization without cardiopulmonary bypass in left main coronary artery stenosis. METHODS: Between October 1996 and October 1998, 67 patients with a left main stem stenosis (LMS) (> 50%) underwent revascularization on beating heart surgery (BHS) and were compared to a cohort of 192 patients with LMS disease that were operated on under cardiopulmonary bypass (CPB) during 1996. RESULTS: Mean age and sex distribution and prevalence of preoperative risk factors were the same in both groups as well as the average number of grafts per patient was 3.1 +/- 0.7 and 2.9 +/- 0.7 in BHS and CPB groups respectively. Perioperative infarction rate (defined arbitrarily as a CK-MB > 100 IUL) was 2.9% in BHS group and 3.1% in CPB group. Postoperative blood transfusion requirements were less in BHS group (38%) compared to CPB group (64%), p < 0.05. Inotropic requirements postoperatively were similar in both groups. Hospital stay was shorter in BHS group (6.8 days) compared to CPB group (7.6 days) although not significant. There was no operative mortality in BHS group whereas 4.7% died postoperatively in CPB group. CONCLUSION: Our experience suggests that non-bypass surgical revascularization is a feasible and safe alternative to conventional cardiopulmonary bypass.

Aged↗

PubMed1999

[Hemodynamic changes during bypass surgeries in the beating heart].

OBJECT: To study the effect of surgical manipulations on patient hemodynamics during beating-heart CABG surgery. METHODS: We continuously monitored the systemic arterial pressure (SAP, n = 31), the pulmonary arterial pressure (PAP, n = 31) and the mixed venous oxygen saturation (SvO2, n = 6) using an Oxymetrix catheter. RESULTS: Patients age ranged from 53 to 85 years old (mean 66.4 +/- 8.5) to whom 3.0 +/- 0.8 distal anastomoses were performed per patient. Stabilization of the heart were done using a "fork-type" stabilizator in all patients, and the target coronaries were clamped proximally and distally to the anastomosis site without pre-conditioning. A SAP decrease was found during the procedure and differed on the coronary territory being worked on: left anterior descending (LAD) (-11 +/- 19%), diagonal (Diag) (-13 +/- 27%), circumflex marginal (CM) (-19 +/- 17%) and right coronary (RC) or posterior descending artery (PDA) (-17 +/- 14%). PAP increase was maximal with the Diag (+47 +/- 84%) and was more important during LAD (+30 +/- 36%) and CM (+21 +/- 48%) than RC/PDA revascularization (+10 +/- 24%). On the other hand, SvO2 changes were found unchanged with any coronary territory. These changes occurred during the stabilization period before vessel occlusion, and were well tolerated by all patients, whom rarely needed inotropic support. No correlation between SvO2, SAP, PAP and occlusion time was found. CONCLUSION: The mobilization and stabilization of the heart using a "fork-type" stabilizator, rather than clamping the coronaries, during beating-heart CABG surgery were responsible for a decreased in SvO2, the SAP and an increase of the PAP. The marked elevation of PAP during revascularization of the diagonal and LAD territory may be explained by a compression of the left ventricle outflow tract. The Trendelenburg maneuver used during revascularization of the marginal and PDA territories may improve hemodynamics by relieving such pressure on the outflow tract and improve venous return.

Aged↗

PubMed1999

[Results of surgery after failed mitral percutaneous dilatation].

OBJECTIVES: Percutaneous balloon mitral valve commissurotomy (BMC) is an alternative to surgical commissurotomy. Complications following BMC includes mitral regurgitation, iatrogenic atrial septal defect, residual mitral stenosis, and pericardial hemorrhage. This study analyzes the outcomes of surgery following failed BMC for mitral stenosis. METHODS: In a series of 298 patients treated with BMC, 53 patients (17.7%) had a complication that necessitated a surgical treatment. Twenty-eight patients needed an immediate surgery before the discharge (group I) and 25 patients were operated on an elective basis (group II). RESULTS: In group I, 27 patients have been operated and one died before the operation. In 21 patients an acute mitral regurgitation occurred, 3 patients had a residual mitral stenosis, and 3 had a left atrial perforation. The operation consisted of 26 mitral valve replacements, 20 concomitant reparations of iatrogenic atrial septal defect, and one open mitral valve commissurotomy. Operative mortality was 3.7% (1 out of 27). In group II, 25 patients have been operated at a mean 18 +/- 14 months after BMC. In the 25 patients the operation was indicated for significant mitral regurgitation (2 + and more). The operation consisted of 25 mitral valve replacements, 9 concomitant reparations of iatrogenic atrial septal defect, 3 patients had also coronary artery bypasses. The operative mortality was 8% (2 out of 25). The echocardiographic score was similar for both groups, it was 8.4 +/- 2.0 in group I and 8.0 +/- 1.5 in group II (P = NS). Despite these complications following failed BMC, surgery appears a safe procedure with an acceptable mortality.

Aged↗

PubMed1998

Prophylactic carotid endarterectomy without arteriography in patients without hemispheric symptoms: surgical morbidity and mortality and long-term follow-up.

Between January 1980 and December 1992, 75 prophylactic carotid endarterectomies (CE) were performed on 72 asymptomatic patients presenting high-grade stenosis of the internal carotid artery (ICA). In all patients preoperative assessment consisted of continuous Doppler or duplex scanning. There were 33 women and 39 men with a mean age of 66 +/- 7 years. Surgical exploration confirmed high-grade ICA stenosis in all patients. Mean transstenotic gradient and residual carotid stump pressure determined in 24 patients were 34 +/- 25 mmHg and 51 +/- 20 mmHg, respectively. Combined operative mortality and neurologic morbidity was 1.3% (one death, no permanent neurologic defect). At 5 years, 74% +/- 8% of patients were free of neurologic complications, 89% +/- 8% of patients were free of neurologic complications affecting the ipsilateral cerebral hemisphere, and actuarial survival was 75% +/- 8%. Most deaths were due to heart-related causes. Multivariate analysis showed that hypertension, age, recurrent stenosis, and contralateral stenosis greater than 50% were risk factors for neurologic complications. When only ipsilateral complications were considered, only hypertension was a risk factor. Based on the results of this study, we conclude that prophylactic CE based only on continuous Doppler or duplex scanning is a reliable and safe procedure. Prophylactic CE was effective in avoiding long-term neurologic complications due to ipsilateral hemispheric lesions. However, the higher incidence of contralateral neurologic complications suggests that close surveillance of contralateral lesions is necessary.

Aged↗

PubMed1998

Off-pump revascularization of multivessel coronary artery disease has a decreased myocardial infarction rate.

BACKGROUND: The advent of new mechanical stabilization devices allows complete coronary artery revascularization on the beating heart without extracorporeal circulation (ECC). OBJECTIVES: To compare retrospectively the short-term outcomes of 40 patients operated without ECC or cardiopulmonary arrest (group 1) with 40 consecutive patients operated with ECC (group 2) by the same surgeon in the period immediately prior to starting the beating-heart technique. RESULTS: The two groups were similar in terms of age (group 1: 64+/-8 vs. group 2: 62+/-10), male/female ratio (group 1: 31/9 vs. group 2: 32/8), presence of unstable angina prior to surgery (group 1: 72.5% vs. group 2: 77.5%), reoperative surgery (group 1: 1.5% vs. group 2: 7.5%), and perioperative risk factors. Group 1 had an average of 2.8+/-0.7 grafts compared to 3.3+/-0.9 grafts in group 2 (P < 0.01). Postoperative myocardial infarction rate (CK-MB > 50 IU) was 12.5% following ECC and 2.5% with the beating-heart technique (P > 0.001). Maximum perioperative CK-MB level was also decreased in group 1 (group 1: 14+/-17 vs. group 2: 46+/-53, P < 0.001). Postoperative arterial lactate dosage (group 1: 3.1+/-1.2 vs. group 2: 3.9+/-1.6, P = 0.02) and a significant increase in creatinine (>50 mM) (group 1: 5% vs. group 2: 18%, P = 0.06) were also decreased less frequent in patients operated on without ECC. A decrease in transfusion needs was also observed (group 1: 40% vs. group 2: 58%). Similar results were obtained for atrial fibrillation, stroke, postoperative use of intra-aortic balloon pumping (IABP), and pulmonary complication rate. CONCLUSIONS: We conclude from our experience with a multivessel coronary disease population, that a decrease in perioperative myocardial infarction and renal damage can be achieved by using the beating-heart technique.

Case-Control Studies↗

PubMed1998

Influence of haemoglobin concentration after extracorporeal circulation on mortality and morbidity in patients undergoing cardiac surgery.

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Adult↗

PubMed1998

Triple coronary artery revascularization on the stabilized beating heart: initial experience.

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.

Aged↗

PubMed1998

Coronary endarterectomy revisited: mid-term angiographic results.

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.

Aged↗

PubMed1998

Retrograde replacement of the thoracic aorta under circulatory arrest and retrograde cerebral perfusion.

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.

Adult↗

PubMed1998

[Peri-operative benefits of beating-heart coronary revascularization in patients with triple vessel disease].

OBJECTIVES: To compare the perioperative benefits of the offpump coronary artery surgery to conventional surgery with cardiopulmonary bypass (CPB) assistance. METHOD: Retrospective study comparing 50 consecutive patients with triple vessel disease (TVD) operated upon with CPB assistance to 50 consecutive patients with TVD operated on beating heart (BH) by the same surgeon between January 1996 and August 1997 at the Montreal Heart Institute. Matching criteria between the 2 groups were: first time operation, normal left ventricular ejection function (LVEF), and coronary TVD. RESULTS: Demographic data and risk factors were comparable in both groups. Unstable angina was the most common surgical indication (CBP: 72%, BH: 62%). The average number of grafts were comparable in both groups (CBP: 3.5 vs 0.6 vs BH: 3.3 +/- 0.4, p = 0.06) as well as the preoperative LVEF (CEC: 60 +/- 1% vs CB: 62 +/- 1.2%, p = 0.38). Arterial lactate count was lower in the BH group during the perioperative period (3.0 +/- 1.0 vs 3.9 +/- 1.7 mM) as well as the maximal CK-MB level (BH: 20 +/- 6.4 vs CBP: 40 +/- 3.5 IU/L, p = 0.003), transfusional needs (CB: 34% vs CEC: 66%, p = 0.003), and postoperative creatinin level (BH: 100 +/- 4.2 vs CBP: 120 +/- 7.1 mM, p = 0.001). Postoperative HB level was also higher in the BH group (110 +/- 14 vs 104 +/- 12, p = 0.001). CONCLUSION: Our data confirm potential benefits from BH surgery on patients affected with triple vessel disease relatively to transfusional needs, and myocardial as well as renal protection.

Angina, Unstable↗

PubMed1998

[Comparison of endothelial reactivity of infrarenal and suprarenal aortic segments in rodents].

OBJECT: Human infrarenal aorta is prone to develop atherosclerotic lesions. Infrarenal aortic blood flow depends on lower limb muscular activity. Blood flow variations cause shear stress variations known to influence endothelial reactivity. The purpose of this study is to compare vascular reactivity of the suprarenal and infrarenal aorta. MATERIAL AND METHODS: Endothelium-dependent relaxation to acetylcholine (ACH) and calcium ionophore (Cal), and endothelium-independent relaxation to sodium nitroprussiate (SNP) in 3 aortic segments (thoracic, abdominal suprarenal and infrarenal) harvested from Sprague-Dawley rats (n = 12) were studied in organ chambers. RESULTS: Endothelium-dependent relaxations to ACH were similar for the 3 aortic segments. However, infrarenal aorta endothelial response to Cal was decreased compared to other segments whereas response to SNP was enhanced. Contractility to vasoconstrictor agonist (phenylephrine and KCl) was diminished compared to the suprarenal segments. CONCLUSION: Endothelial reactivity is not homogeneous throughout the rat aorta. Endothelial reactivity to Cal seems decreased in the infrarenal aorta which suggests a diminished nitric oxide synthase activity. The increased sensitivity of the infrarenal aorta to nitric oxide donor such as SNP suggests a compensatory mechanism.

Acetylcholine↗