Roupen Hatzakorzian

Initial Results of Posterior Leaflet Extension for Severe Type IIIb Ischemic Mitral Regurgitation

Background— Management of severe ischemic mitral regurgitation remains difficult with disappointing early and intermediate-term surgical results of valve repair. Methods and Results— Forty-four patients with severe (4+) Carpentier type IIIb ischemic mitral regurgitation underwent mitral valve repair, with or without surgical revascularization, by posterior leaflet extension with a patch of bovine pericardium and a remodeling annuloplasty. Serial echocardiography was performed preoperatively, intraoperatively, and postoperatively to assess mitral valve competence. The postoperative functional status of patients was assessed. The average Parsonnet score was 38±13. Thirty-day mortality was 11%, and late mortality was 14%. Mean follow-up was 38 months. The actuarial freedom from moderate or severe recurrent mitral regurgitation was 90% at 2 years, whereas 90% of patients were in New York Heart Association class I at 2 years. Conclusion— Posterior leaflet extension with annuloplasty of the mitral valve for severe type IIIb ischemic regurgitation is a safe, effective method that provides good early and intermediate-term competence of the mitral valve and therefore good functional status.

Cardioprotective Effects of Glucose and Insulin Administration While Maintaining Normoglycemia (GIN Therapy) in Patients Undergoing Coronary Artery Bypass Grafting

CONTEXT Coronary artery bypass grafting (CABG) is complicated by ischemia-reperfusion injury jeopardizing myocyte survival. OBJECTIVE The aim of the study was to investigate whether glucose and insulin administration, while maintaining normoglycemia (GIN therapy) using a hyperinsulinemic-normoglycemic clamp technique, is cardioprotective in patients undergoing CABG. DESIGN AND SETTING We conducted a randomized controlled trial at a tertiary care university teaching hospital. PATIENTS We studied 99 patients undergoing elective CABG. INTERVENTION Patients were randomly assigned to receive either GIN from the beginning of surgery until 24 h after CABG (GIN, n = 49) or standard metabolic care (control, n = 50). MAIN OUTCOME MEASURES We measured plasma concentrations of cardiac troponin I and free fatty acids, cardiac function as assessed by transesophageal echocardiography, glycogen content, glycogen synthase activity, and the expression of AMP-activated protein kinase (AMPK) and protein kinase B (AKT) in cardiomyocytes. RESULTS Patients receiving GIN therapy showed an attenuated release of cardiac troponin I (P < 0.05) and improved myocardial function (P < 0.05). Systemic free fatty acid concentrations were suppressed (P < 0.05), whereas intracellular glycogen content and glycogen synthase activity were not altered. The AMPK activity remained unchanged during ischemia in the GIN group, whereas it increased in the control group (P < 0.05). Enhanced AKT phosphorylation before ischemia was observed (P < 0.05) in the presence of GIN. However, there was no evidence for AKT-dependent AMPK inhibition. CONCLUSIONS GIN therapy protects the myocardium and inhibits ischemia-induced AMPK activation.

Fasting blood glucose levels in patients presenting for elective surgery

OBJECTIVE The incidence of diabetes mellitus (DM) is increasing worldwide; however, its diagnosis is often delayed. Identifying patients with abnormal fasting blood glucose (FBG) levels preoperatively may have important implications for immediate and long-term outcomes. The aim of the present study was to determine the prevalence of impaired fasting glucose (IFG) and provisional diagnosis of DM (PDD) with potential risk factors in patients presenting for elective surgery. METHODS We measured FBG in consecutive adult patients undergoing elective non-cardiac surgery from September 2006 to August 2007. Patient age, sex, body mass index, and FBG were collected in the morning of their scheduled intervention. FBG was classified according to the World Health Organization categorization. Patients with a history of DM were excluded from the final analysis. The prevalence of IFG and PDD and odds ratio for risk factors were calculated. RESULTS Four hundred ninety-three patients without a prior diagnosis of DM were sampled; 19.3% (95 of 493) had IFG and 6.5% (32 of 493) had PDD. Male subjects had a greater risk of PDD than female subjects (odds ratio 2.5, 95% confidence interval 1.2-5.5, P = 0.017). Increased body mass index was not a risk factor for IFG or PDD. The prevalence of IFG but not of PDD had a tendency to increase with age after 40 y. CONCLUSION More than 25% of patients without a prior diagnosis of DM presenting for elective surgery had increased FBG levels. Obtaining this information may initiate not only an earlier detection of DM in some patients but also affect acute perioperative management and outcomes.

Albumin synthesis in surgical patients

Albumin plasma concentrations are being used as indicators of nutritional status and hepatic function based on the assumption that plasma levels reflect the rate of albumin synthesis. However, it has been shown that albumin levels are not reliable markers of albumin synthesis under a variety of clinical conditions including inflammation, malnutrition, diabetes mellitus, liver disease, and surgical tissue trauma. To date, only a few studies have measured albumin synthesis in surgical and critically ill patients. This review summarizes the findings from these studies, which used different tracer methodology in various surgical or critically ill patient populations. The results indicate that the fractional synthesis rate of albumin appears to decrease during surgery, followed by an increase during the postoperative phase. In the early postoperative phase, albumin fractional synthesis rate can be stimulated by perioperative nutrition, if enough amino acids are being provided and if nutrition is being initiated before the operation. The physiologic meaning of albumin synthesis after surgery, however, still needs to be further clarified.

The anabolic effect of perioperative nutrition depends on the patient's catabolic state before surgery.

Objective:We tested the hypothesis that the anabolic effect of hypocaloric, isonitrogenous nutrition in patients undergoing colorectal surgery depends on the patients preoperative catabolic state. Background:Although there is evidence to suggest that total parenteral nutrition more effectively spares protein in depleted than in nondepleted cancer patients, the influence of preoperative catabolism on the anabolic effects of hypocaloric nutrition in patients undergoing elective surgery is unknown. Methods:Seventeen patients undergoing colorectal surgery received intravenous infusion of glucose with amino acids. Feeding was administered over 72 hours, from 24 hours before until 48 hours after surgery. Glucose provided 50% of the patients measured resting energy expenditure. Amino acids provided 20% of the resting energy expenditure. Whole-body leucine balance (difference between the incorporation of leucine into protein = protein synthesis and endogenous leucine release = proteolysis) was determined using L-[1-13C]leucine kinetics before and 2 days after surgery. We analyzed the association between the postoperative increase in leucine balance and the following factors: preoperative leucine balance, protein breakdown, weight loss, oxygen consumption, circulating concentrations of glucose, free fatty acids, insulin, glucagon, cortisol, albumin, age, duration of surgery, and blood loss. Results:Of 6 potentially relevant variables, 4 (weight loss, protein breakdown, albumin, and cortisol) were removed because they were not significant during the stepwise linear regression procedure. Leucine balance and age were the remaining 2 factors that remained with the final regression model: &Dgr;leucine balance = 19.1 − (0.20 × age [years]) − (0.58) × leucine balancepreOP). Conclusions:We demonstrate a significant association between the degree of preoperative catabolism, the patients age, and the anabolic effect of hypocaloric nutrition (ClinicalTrials.gov registration ID: NCT01414946).

Perioperative tight glucose control with hyperinsulinemic-normoglycemic clamp technique in cardiac surgery

OBJECTIVE Previous attempts to achieve tight glucose control in surgical patients were associated with a significant incidence of hypoglycemia. The purpose of this study was to evaluate the efficacy of perioperative glucose and insulin administration while maintaining normoglycemia using a hyperinsulinemic-normoglycemic clamp technique. METHODS We studied 70 non-diabetic and 40 diabetic patients undergoing cardiac procedures. Before induction of anesthesia, insulin was administered at 5 mU·kg(-1)·min(-1). Blood glucose (BG) concentrations were determined every 15-30 min. Dextrose 20% was infused at a rate adjusted to maintain BG within 3.5-6.1 mmol/L. At the end of surgery, insulin infusion was decreased to 1 mU·kg(-1)·min(-1) and continued for 24h. The mean ± standard deviation of BG and the percentage of BG values within the target range were calculated perioperatively. Episodes of severe hypoglycemia, i.e., BG <2.2 mmol/L, were recorded. RESULTS The mean BG remained within target at all times. Normoglycemia in non-diabetic patients was achieved in 92.8% of measurements during and in 83.2% after surgery. In diabetic patients 87.4% of values were within target intraoperatively and 76.7% after surgery. The rate of severe hypoglycemia was 2.7% (three patients). In non-diabetic patients the incidence of severe hypoglycemia was 0.2% of measurements during and 0.1% after surgery. Diabetic patients showed only one episode of severe hypoglycemia after surgery (0.1%). CONCLUSION Perioperative use of a hyperinsulinemic-normoglycemic clamp technique established and maintained normoglycemia in patients undergoing cardiac surgery with little risk of hypoglycemia.

Statin Intake Is Associated With Decreased Insulin Sensitivity During Cardiac Surgery

OBJECTIVE Surgical trauma impairs intraoperative insulin sensitivity and is associated with postoperative adverse events. Recently, preprocedural statin therapy is recommended for patients with coronary artery disease. However, statin therapy is reported to increase insulin resistance and the risk of new-onset diabetes. Thus, we investigated the association between preoperative statin therapy and intraoperative insulin sensitivity in nondiabetic, dyslipidemic patients undergoing coronary artery bypass grafting. RESEARCH DESIGN AND METHODS In this prospective, nonrandomized trial, patients taking lipophilic statins were assigned to the statin group and hypercholesterolemic patients not receiving any statins were allocated to the control group. Insulin sensitivity was assessed by the hyperinsulinemic-normoglycemic clamp technique during surgery. The mean, SD of blood glucose, and the coefficient of variation (CV) after surgery were calculated for each patient. The association between statin use and intraoperative insulin sensitivity was tested by multiple regression analysis. RESULTS We studied 120 patients. In both groups, insulin sensitivity gradually decreased during surgery with values being on average ∼20% lower in the statin than in the control group. In the statin group, the mean blood glucose in the intensive care unit was higher than in the control group (153 ± 20 vs. 140 ± 20 mg/dL; P < 0.001). The oscillation of blood glucose was larger in the statin group (SD, P < 0.001; CV, P = 0.001). Multiple regression analysis showed that statin use was independently associated with intraoperative insulin sensitivity (β = −0.16; P = 0.03). CONCLUSIONS Preoperative use of lipophilic statins is associated with increased insulin resistance during cardiac surgery in nondiabetic, dyslipidemic patients.

High-Dose Insulin Administration Improves Left Ventricular Function After Coronary Artery Bypass Graft Surgery

OBJECTIVE To test the hypothesis that the intravenous administration of high doses of insulin while maintaining normoglycemia (GIN therapy) improves myocardial function after coronary artery bypass graft (CABG) surgery. DESIGN A prospective, randomized clinical trial. SETTING A university hospital. PARTICIPANTS Forty patients undergoing elective CABG surgery. INTERVENTIONS Patients were randomized to the GIN or control group. Applying the principles of the hyperinsulinemic-normoglycemic clamp technique in the GIN group, insulin was administered at 5 mU/kg/min during surgery. Glucose 20% was infused at a rate adjusted to maintain blood glucose (BG) between 4.0 and 6.0 mmol/L. Patients in the control group received insulin on a sliding scale, also aiming at normoglycemia. MEASUREMENTS AND MAIN RESULTS Systemic hemodynamic parameters included heart rate, mean arterial pressure, pulmonary artery wedge pressure, vascular resistance index, and cardiac index (CI). Left ventricular function was assessed by transesophageal echocardiography using the myocardial performance index (MPI) as a parameter of global left ventricular function, the fractional area change (FAC) for systolic function, and flow propagation velocity for diastolic function before and after surgery. All patients receiving GIN therapy were hyperinsulinemic (3,474 ± 1,204 pmol/L) and normoglycemic, showing a lower mean BG concentration (4.9 ± 0.5 mmol/L) than patients in the control group (8.2 ± 2.0 mmol/L). Patients receiving GIN therapy had an increased CI after surgery compared with the control group (p = 0.005). The GIN therapy was associated with improved MPI and FAC values when compared with standard care. Also, there was no difference in the parameters indicating left ventricular diastolic function. CONCLUSIONS Intraoperative GIN therapy improves global and systolic left ventricular function after CABG surgery.

Predicting early epidurals: association of maternal, labor, and neonatal characteristics with epidural analgesia initiation at a cervical dilation of 3 cm or less

Background Retrospective studies have associated early epidural analgesia with cesarean delivery, but prospective studies do not demonstrate a causal relationship. This suggests that there are other variables associated with early epidural analgesia that increase the risk of cesarean delivery. This study was undertaken to determine the characteristics associated with early epidural analgesia initiation. Methods Information about women delivering at 37 weeks or greater gestation with epidural analgesia, who were not scheduled for cesarean delivery, was extracted from the McGill Obstetric and Neonatal Database. Patients were grouped into those who received epidural analgesia at a cervical dilation of ≤3 cm and >3 cm. Univariable and multivariable logistic regression was used to determine the maternal, neonatal, and labor characteristics that increased the risk of inclusion in the early epidural group. Results Of the 13,119 patients analyzed, multivariable regression demonstrated odds ratios (OR) of 2.568, 5.915 and 10.410 for oxytocin augmentation, induction, and dinoprostone induction of labor (P < 0.001). Increasing parity decreased the odds of early epidural analgesia (OR 0.780, P < 0.001), while spontaneous rupture of membranes (OR 1.490) and rupture of membranes before labor commenced (OR 1.288) were also associated with early epidural analgesia (P < 0.001). Increasing maternal weight (OR 1.049, P = 0.002) and decreasing neonatal weight (OR 0.943, P < 0.001) were associated with increasing risk of early epidural analgesia. Conclusion Labor augmentation and induction, nulliparity, rupture of membranes spontaneously and before labor starts, increasing maternal weight, and decreasing neonatal weight are associated with early epidural analgesia. Many of these variables are also associated with cesarean delivery.

Decreased heart rate and blood pressure in a recent cardiac transplant patient after spinal anesthesia

PurposeTo describe the cardiovascular effects of neuraxial blockade in a heart transplant patient.Clinical featuresA 69-yr-old 70-kg male underwent orthotopic heart transplant (bicaval anastomosis technique) for ischemic cardiomyopathy. Five months after transplantation, the patient underwent a transurethral bladder tumour resection under spinal anesthesia. Two millilitres of bupivacaine 0.75% (15 mg) were injected intrathecally at L3–4 and the patient remained seated for approximately 20 sec prior to assuming the lithotomy position. Subsequently, both blood pressure (BP) and heart rate (HR) diminished gradually (BP and HR immediately pre-spinal: 113 mmHg (mean arterial pressure) and 92 beats·min−1, respectively; nadir BP and HR: 94 mmHg (16.8% decrease) 30 min postspinal and 73 beats·min−1 (20.7% decrease) 40 min postspinal, respectively). HR and mean BP were highly correlated (r = 0.9410,P < 0.0001, R2 = 0.8854). The dermatome level of neuraxial anesthesia, determined by sensitivity to pin prick, was T8 (five minutes) and T6 (ten minutes) postinjection of spinal anesthetic. Control patients (n = 10) undergoing elective urological procedures with identical anesthesia management demonstrated very similar cardiovascular responses.ConclusionsAlthough cardiac transplant patients may tolerate neuraxial anesthesia admirably, a fall in HR may ensue which theoretically could have important physiological consequences. It is argued that the change in HR in the transplanted patient was mediated by mechanisms intrinsic to the transplanted heart and/or by reduced catecholamine secretion from the adrenal medulla. It is emphasized that HR changes observed in cardiac transplant patients do not necessarily imply reinnervation of the transplanted organ.RésuméObjectifDécrire les effets cardiovasculaires du blocage neuraxial chez un greffé cardiaque.Éléments cliniquesUn homme de 69 ans et 70 kg a subi une transplantation cardiaque orthotopique, selon la technique d’anastomose bicave, pour une cardiomyopathie ischémique. Cinq mois après, il a subi la résection transurétrale d’une tumeur vésicale sous rachi-anesthésie. L’injection intrathécale de 2 mL de bupivacaïne à 0,75% (15 mg) a été faite à L3–4 et le patient est demeuré assis environ 20 sec avant d’adopter la position de lithotomie. La tension artérielle (TA) et la fréquence cardiaque (FC) ont ensuite diminué graduellement (TA et FC juste avant la rachianesthésie : 113 mmHg (tension artérielle moyenne) et 92 battements·min−1 ; TA et FC minimales : 94 mmHg (baisse de 16,8 %) 30 min après la rachianesthésie et 73 battements·min−1 (baisse de 20,7 %) 40 min après la rachianesthésie. La FC et la TA moyenne ont été en forte corrélation (r =0,9410, P < 0,0001, R2 =0,8854). Le niveau de l’anesthésie neuraxiale, déterminé par la sensibilité à la piqûre, était de T8 (cinq minutes) et T6 (dix minutes) après l’injection de l’anesthésique rachidien. Des patients (n = 10) qui ont subi ultérieurement une intervention urologique réglée avec une anesthésie identique ont démontré des réponses cardiovasculaires similaires.ConclusionMême si les greffés cardiaques peuvent tolérer admirablement l’anesthésie neuraxiale, une chute de la FC peut survenir et entraïner, en théorie, d’importantes conséquences physiologiques. On peut penser que la modification de la FC chez les greffés relevait de mécanismes intrinsèques au cœur transplanté et/ou de la sécrétion réduite de catécholamines provenant de la médullaire surrénale. Il faut souligner que les changements de FC chez les greffés cardiaques ne touche pas nécessairement la réinnervation de l’organe transplanté.