Biomedical subjects

Kevin Lachapelle

Publications and source records attributed to Kevin Lachapelle.

5 recordsLinked to original sources

PubMed2006

Clinical presentation, temporal relationship, and outcome in thirty-three patients with type 2 heparin-induced thrombocytopenia after cardiotomy.

BACKGROUND: Type 2 heparin-induced thrombocytopenia is an uncommon but often fatal complication of heparin, frequently difficult to diagnose after cardiac surgery. In this series, we record the clinical presentation, temporal relationship, and treatment outcome of patients diagnosed with heparin-induced thrombocytopenia postoperatively. METHODS: Thirty-three consecutive patients (1.1%) with a diagnosis of heparin-induced thrombocytopenia established by a greater than 50% drop in platelet count with or without a thrombotic event and a positive platelet factor-4 assay were reviewed. We recorded the clinical presentation, the time to presentation, treatment, and outcome (thrombosis, mortality). Univariate analysis was performed on 13 preoperative, operative, and postoperative variables. RESULTS: The cohort was at increased mortality risk as a result of age (69.4 years), reduced cardiac function (46.8%), nonbypass operations (57.6%), emergency surgery (21.2%), and implantation of three assist devices. The mean time to suspect heparin-induced thrombocytopenia postoperatively was 5.4 days, with 22 cases (66.6%) occurring within 5 days. All patients had previous (within 3 months) exposure to heparin, and 66.6% had ongoing treatment with heparin before surgery. Overall mortality was 33%; thrombotic complications occurred in 15 patients (45.5%), with a mortality of 7 (46.6%) despite immediate cessation of heparin and treatment with a nonheparin analog. Thrombocytopenia without thrombosis occurred in 18 patients (54.5%), but a subgroup of 5 patients with nonthrombotic complications accounted for the 4 (22.2%) deaths. CONCLUSIONS: Heparin-induced thrombocytopenia after cardiac surgery is uncommon but may occur within 5 days of surgery, further complicating diagnosis and treatment. Thrombotic complications result in a high mortality despite treatment with a nonheparin analog, and a subgroup of patients with thrombocytopenia fared poorly.

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PubMed2005

Reappraisal of recent clinical trials of angiogenic therapy in myocardial ischemia.

We review the clinical trials of angiogenic therapy for myocardial ischemia, focusing on why the results are unsatisfactory in more recent larger and better designed trials. Critical reappraisal of such trials, in view of the pathophysiologic complexity of the angiogenic process at a molecular level, suggests that the strategy of therapies based on a single growth factor protein or gene may not be adequate for optimal therapeutic response.

Angiogenesis Inducing Agents↗

PubMed2004

Maintenance of normoglycemia during cardiac surgery.

We used the hyperinsulinemic normoglycemic clamp technique, i.e., infusion of insulin at a constant rate combined with dextrose titrated to clamp blood glucose at a specific level, to preserve normoglycemia during elective cardiac surgery. Ten nondiabetic and seven diabetic patients entered the clamp protocols. Perioperative glucose control was also assessed in 19 nondiabetic and 11 diabetic patients (control group) receiving a conventional insulin infusion sliding scale. In patients of the clamp group, a priming bolus of insulin (2 U) was started before the induction of anesthesia followed by infusions of insulin at 5 mU. kg(-1). min(-1) and of variable amounts of dextrose. Arterial blood glucose was measured every 5 min in the clamp group and every 20 min in the control group. Control of normoglycemia was defined as > or =95% of the glucose levels within 4.0-6.0 mmol/L. Glucose concentration was recorded before surgery, 15 min before cardiopulmonary bypass (CPB), during early and late CPB, and at sternal closure. Patients of the control group became progressively hyperglycemic during surgery (late CPB; nondiabetics, 9.0 +/- 3.2 mmol/L; diabetics, 10.1 +/- 3.6 mmol/L), whereas normoglycemia was achieved in the study group (late CPB; nondiabetics, 5.5 +/- 0.7 mmol/L; diabetics, 4.9 +/- 0.6 mmol/L; P < 0.05 versus control group). In conclusion, it seems that normal blood glucose concentration during open heart surgery can be reliably maintained in nondiabetic and diabetic patients by using the hyperinsulinemic normoglycemic clamp technique.

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PubMed2003

Therapeutic angiogenesis using autologous bone marrow stromal cells: improved blood flow in a chronic limb ischemia model.

BACKGROUND: We evaluated the effect of autologous marrow stromal cells (MSCs) on neovascularization and blood flow in an animal model of chronic limb ischemia. METHODS: Chronic hind limb ischemia was created by ligating the left common iliac artery of male Lewis rats. Three weeks after ligation, 5.0 million LacZ+MSCs (n = 10) or culture medium (n = 10) were injected into the anteromedial muscle compartment of the left thigh. At 4 and 6 weeks after injection, half the animals (n = 5) from each group underwent femoral artery ultrasonic blood flow measurements of the ischemic and nonischemic limbs to obtain a flow ratio. The animals also underwent angiography and measurements of blood vessel density and arteriolar density. Qualitative histologic assessment of the limb muscles was performed. RESULTS: LacZ+MSCs were found to differentiate into endothelium (F VIII+), vascular smooth muscle (positive a-smooth muscle actin), skeletal muscle (positive desmin), and adipocytes. Ischemic hind limbs where MSCs were implanted had greater vascular density and arteriolar density than control limbs (p < 0.001). Femoral artery flow index (left femoral artery flow/right femoral artery flow) was 0.89 +/- 0.12 and 0.90 +/- 0.06 for rats injected with MSCs measured at 4- and 6-weeks, respectively, compared with 0.50 +/- 0.15 and 0.50 +/- 0.10 for the control rats (p < 0.001). Angiography demonstrated reconstitution of the left femoral artery in rats that received MSC implantation through pelvic and abdominal wall collateral formation. CONCLUSIONS: Local MSC implantation induces a neovascular response resulting in a significant increase in blood flow to the ischemic limb. Marrow stromal cells are also capable of spontaneously regenerating the various components of muscular tissues.

Animals↗

PubMed2002

Sutureless patch technique for postinfarction left ventricular rupture.

BACKGROUND: Left ventricular free wall rupture is an uncommon but catastrophic event after myocardial infarction and is associated with a high mortality. After prompt diagnosis some patients may be salvaged with immediate surgical intervention. Surgical techniques used to seal the rupture vary, as few surgeons have experience with this pathologic process. We report our experience using a sutureless patch technique to treat this entity. METHODS: A review of 6 consecutive patients during an 8-year period who were referred to one cardiac unit with postinfarction left ventricular rupture was conducted. RESULTS: There were 3 men and 3 women with an average age of 71.8 years. All were hemodynamically unstable, and 4 were in electromechanical dissociation. Echocardiography confirmed the diagnosis in 5 patients, and cardiac catheterization had been performed in 4 before rupture. All patients were treated promptly with fluid, inotropic agents, and, if needed, cardiopulmonary resuscitation and pericardiocentesis. Resuscitation was continued in the operating room, and the myocardial tear was sealed with a generous patch of unsupported felt secured to the heart with cyanoacrylate glue. Coronary artery bypass grafting was performed in 3 patients if the anatomy was known. All patients survived to the intensive care unit. One death occurred as a result of severe neurologic injury. Five patients were discharged from the hospital, and all were alive 2 months to 7.5 years after operation. CONCLUSIONS: A sutureless patch technique for the treatment of postinfarction rupture is simple, effective, and associated with a favorable outcome.

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