Jorge Mascaro

Remote Ischemic Preconditioning in Human Coronary Artery Bypass Surgery From Promise to Disappointment

Background— We assessed whether remote ischemic preconditioning (RIPC) improves myocardial, renal, and lung protection after on-pump coronary surgery. Methods and Results— This was a single-center, prospective, randomized (1:1), placebo-controlled trial. Patients, investigators, anesthetists, surgeons, and critical care teams were blinded to group allocation. Subjects received RIPC (or placebo) stimuli (×3 upper limb (or dummy arm), 5-minute cycles of 200 mm Hg cuff inflation/deflation) before aortic clamping. Anesthesia, perfusion, cardioplegia, and surgical techniques were standardized. The primary end point was 48-hour area under the curve (AUC) troponin T (cTnT) release. Secondary end points were 6-hour and peak cTnT, ECG changes, cardiac index, inotrope and vasoconstrictor use, renal dysfunction, and lung injury. Hospital survival was 99.4%. Comparing placebo and RIPC, median (interquartile range) AUC 48-hour cTnT (ng/mL−1/48 h−1); 28 (19, 39) versus 30 (22, 38), 6-hour cTnT (ng/mL−1); 0.93(0.59, 1.35) versus 1.01(0.72, 1.43), peak cTnT (ng/mL−1); 1.02 (0.74, 1.44) versus 1.04 (0.78, 1.51), de novo left bundle-branch block (4% versus 0%) and Q waves (5.3% versus 5.5%), serial cardiac indices, intraaortic balloon pump usage (8.5% versus 7.5%), inotrope (39% versus 50%) and vasoconstrictor usage (66% versus 64%) were not different. Dialysis requirement (1.2% versus 3.8%), peak creatinine (median [interquartile range], 1.2 mg/dL−1 (1.1, 1.4) versus 1.2 (1.0, 1.4)), and AUC urinary albumin-creatinine ratios 69 (40, 112) versus 58 (32, 85) were not different. Intubation times; median (interquartile range), 937 minutes(766, 1402) versus 895(675, 1180), 6-hour; 278 (210, 338) versus 270 (218, 323) and 12-hour pO2:FiO2 ratios 255 (195, 323) versus 263 (210, 308) were similar. Conclusions— In contrast to prior smaller studies, RIPC did not reduce troponin release, improve hemodynamics, or enhance renal or lung protection. Clinical Trial Registration— URL: http://www.ukcrn.org.uk. Unique identifier: 4659.

The haemodynamic effects of adjunctive hormone therapy in potential heart donors: a prospective randomized double-blind factorially designed controlled trial

AIMS The aim of this study was to assess the haemodynamic effects of tri-iodothyronine (T3) and methylprednisolone in potential heart donors. METHODS AND RESULTS In a prospective randomized double-blind trial, 80 potential cardiac donors were allocated to receive T3 (0.8 microg kg(-1) bolus; 0.113 microg kg(-1) h(-1) infusion) (n = 20), methylprednisolone (1000 mg bolus) (n = 19), both drugs (n = 20), or placebo (n = 21) following initial haemodynamic assessment. After hormone or placebo administration, cardiac output-guided optimization was initiated, using vasopressin as a pressor and weaning norepinephrine and inotropes. Treatment was administered for 5.9 +/- 1.3 h until retrieval or end-assessment. Cardiac index increased significantly (P < 0.001) but administration of T3 and methylprednisolone alone or in combination did not affect this change or the heart retrieval rate. Thirty-five per cent (14/40) of initially marginal or dysfunctional hearts were suitable for transplant at end-assessment. At end-assessment, 50% of donor hearts fulfilled criteria for transplant suitability. CONCLUSION Cardiac output-directed donor optimization improves donor circulatory status and has potential to increase the retrieval rate of donor hearts. Tri-iodothyronine and methylprednisolone therapy do not appear to acutely affect cardiovascular function or yield.

Glucose-insulin-potassium and tri-iodothyronine individually improve hemodynamic performance and are associated with reduced troponin I release after on-pump coronary artery bypass grafting.

Background— Both glucose-insulin-potassium (GIK) and tri-iodothyronine (T3) may improve cardiovascular performance after coronary artery surgery (CABG) but their effects have not been directly compared and the effects of combined treatment are unknown. Methods and Results— In 2 consecutive randomized double-blind placebo-controlled trials, in patients undergoing first time isolated on-pump CABG between January 2000 and September 2004, 440 patients were recruited and randomized to either placebo (5% dextrose) (n=160), GIK (40% dextrose, K+ 100 mmol · L−1, insulin 70 u · L−1) (0.75 mL · kg−1 h−1) (n=157), T3 (0.8 &mgr;g · kg−1 followed by 0.113 &mgr;g · kg−1 h−1) (n=63) or GIK+T3 (n=60). GIK/placebo therapy was administered from start of operation until 6 hours after removal of aortic cross-clamp (AXC) and T3/placebo was administered for a 6-hour period from removal of AXC. Serial hemodynamic measurements were taken up to 12 hours after removal of AXC and troponin I (cTnI) levels were assayed to 72 hours. Cardiac index (CI) was significantly increased in both the GIK and GIK/T3 group in the first 6 hours compared with placebo (P<0.001 for both) and T3 therapy (P=0.009 and 0.029, respectively). T3 therapy increased CI versus placebo between 6 and 12 hours after AXC removal (P=0.01) but combination therapy did not. Release of cTnI was lower in all treatment groups at 6 and 12 hours after removal of AXC. Conclusions— Treatment with GIK, T3, and GIK/T3 improves hemodynamic performance and results in reduced cTnI release in patients undergoing on-pump CABG surgery. Combination therapy does not provide added hemodynamic effect.

Glucose-Insulin-Potassium Reduces the Incidence of Low Cardiac Output Episodes After Aortic Valve Replacement for Aortic Stenosis in Patients With Left Ventricular Hypertrophy Results From the Hypertrophy, Insulin, Glucose, and Electrolytes (HINGE) Trial

Background— Patients undergoing aortic valve replacement for critical aortic stenosis often have significant left ventricular hypertrophy. Left ventricular hypertrophy has been identified as an independent predictor of poor outcome after aortic valve replacement as a result of a combination of maladaptive myocardial changes and inadequate myocardial protection at the time of surgery. Glucose-insulin-potassium (GIK) is a potentially useful adjunct to myocardial protection. This study was designed to evaluate the effects of GIK infusion in patients undergoing aortic valve replacement surgery. Methods and Results— Patients undergoing aortic valve replacement for aortic stenosis with evidence of left ventricular hypertrophy were randomly assigned to GIK or placebo. The trial was double-blind and conducted at a single center. The primary outcome was the incidence of low cardiac output syndrome. Left ventricular biopsies were analyzed to assess changes in 5′ adenosine monophosphate–activated protein kinase (AMPK), Akt phosphorylation, and protein O-linked &bgr;-N-acetylglucosamination (O-GlcNAcylation). Over a 4-year period, 217 patients were randomized (107 control, 110 GIK). GIK treatment was associated with a significant reduction in the incidence of low cardiac output state (odds ratio, 0.22; 95% confidence interval, 0.10 to 0.47; P=0.0001) and a significant reduction in inotrope use 6 to 12 hours postoperatively (odds ratio, 0.30; 95% confidence interval, 0.15 to 0.60; P=0.0007). These changes were associated with a substantial increase in AMPK and Akt phosphorylation and a significant increase in the O-GlcNAcylation of selected protein bands. Conclusions— Perioperative treatment with GIK was associated with a significant reduction in the incidence of low cardiac output state and the need for inotropic support. This benefit was associated with increased signaling protein phosphorylation and O-GlcNAcylation. Multicenter studies and late follow-up will determine whether routine use of GIK improves patient prognosis. Clinical Trial Registration— URL: http://www.controlled-trials.com. Reference number: ISRCTN 05758301.

Patient-Prosthesis Mismatch in Patients With Aortic Stenosis Undergoing Isolated Aortic Valve Replacement Does Not Affect Survival

BACKGROUND Data suggest that patient-prosthesis mismatch (PPM) adversely effects late survival after aortic valve replacement (AVR). This study examined the incidence and implications of PPM in patients undergoing isolated AVR. METHODS Prospectively collected data on patients undergoing isolated AVR for aortic stenosis between January 1, 1997 and December 31, 2007 were analyzed. The projected effective valve orifice area from in vivo data was indexed to body surface area (EOAi). PPM was defined as moderate for EOAi of < or = 0.85 cm(2)/m(2) and severe if < or = 0.6 cm(2)/m(2). The reference group comprised patients with EOAi > 0.85 cm(2)/m(2). The effect of PPM on postoperative survival was assessed by multivariate analysis. RESULTS Of 801 patients, PPM was severe in 48 (6.0%), moderate in 462 (57.8%), and nonexistent in 291 (36.4%). Mismatch was associated with increasing age and female gender, thus resulting in an increase in the EuroSCORE (reference group, 4.9 +/- 2.6; moderate PPM, 5.8 +/- 2.4; and severe PPM, 6.1+/-2.1; p < 0.001). PPM did not significantly increase hospital mortality. Four deaths occurred in the reference group (1.4%), 12 in the moderate PPM (2.6%), and none in the severe PPM group (p = 0.311). The 5-year survival estimates were 83% in reference, 86% in moderate PPM, and 89% in severe PPM (p = 0.25). By multivariate analysis, PPM was not an independent risk factor for reduced in-hospital or late survival. CONCLUSIONS Moderate PPM is common in patients undergoing AVR for aortic stenosis, but severe mismatch is rare. Patients with PPM have similar early and late postoperative survival rate.

The Proinflammatory Environment in Potential Heart and Lung Donors: Prevalence and Impact of Donor Management and Hormonal Therapy

Background. Brain stem death can elicit a potentially manipulable cardiotoxic proinflammatory cytokine response. We investigated the prevalence of this response, the impact of donor management with tri-iodothyronine (T3) and methylprednisolone (MP) administration, and the relationship of biomarkers to organ function and transplant suitability. Methods. In a prospective randomized double-blinded factorially designed study of T3 and MP therapy, we measured serum levels of interleukin-1 and -6 (IL-1 and IL-6), tumor necrosis factor-alpha (TNF-&agr;), C-reactive protein, and procalcitonin (PCT) levels in 79 potential heart or lung donors. Measurements were performed before and after 4 hr of algorithm-based donor management to optimize cardiorespiratory function and ±hormone treatment. Donors were assigned to receive T3, MP, both drugs, or placebo. Results. Initial IL-1 was elevated in 16% donors, IL-6 in 100%, TNF-&agr; in 28%, CRP in 98%, and PCT in 87%. Overall biomarker concentrations did not change between initial and later measurements and neither T3 nor MP effected any change. Both PCT (P =0.02) and TNF-&agr; (P =0.044) levels were higher in donor hearts with marginal hemodynamics at initial assessment. Higher PCT levels were related to worse cardiac index and right and left ventricular ejection fractions and a PCT level more than 2 ng·mL−1 may attenuate any improvement in cardiac index gained by donor management. No differences were observed between initially marginal and nonmarginal donor lungs. A PCT level less than or equal to 2 ng·mL−1 but not other biomarkers predicted transplant suitability following management. Conclusions. There is high prevalence of a proinflammatory environment in the organ donor that is not affected by tri-iodothyronine or MP therapy. High PCT and TNF-&agr; levels are associated with donor heart dysfunction.

Mild renal dysfunction predicts in-hospital mortality and post-discharge survival following cardiac surgery

OBJECTIVES To assess the impact of preoperative renal dysfunction on in-hospital mortality and late survival outcome following adult cardiac surgery. METHODS Prospectively collected data were analysed on 7621 consecutive patients not requiring preoperative renal-replacement therapy, who underwent CABG, valve surgery or combined procedures from 1/1/98 to 1/12/06. Preoperative estimated glomerular filtration rate was calculated using Cockcroft-Gault formula. Patients were classified in the four chronic kidney disease (CKD) stage classes defined by the National Kidney Foundation Disease Outcome Quality Initiative Advisory Board. Late survival data were obtained from the UK Central Cardiac Audit Database. RESULTS There were 243 in-hospital deaths (3.2%). There was a stepwise increase in operative mortality with each CKD class independent of the type of surgery. Multivariate analysis confirmed CKD class to be an independent predictor of in-hospital mortality (class 2 OR 1.45, 95% CI 1.1-2.35, p=0.001; class 3 OR 2.8, 95% CI 1.68-4.46, p=0.0001; class 4 OR 7.5, 95% CI 3.76-15.2, p=0.0001). The median follow-up after surgery was 42 months (IQR 18-74) and there were 728 late deaths. Survival analysis using a Cox regression model confirmed CKD class to be an independent predictor of late survival (class 2 HR 1.2, 95% CI 1.1-1.6, p=0.0001; class 3 HR 1.95, 95% CI 1.6-2.4, p=0.0001; and class 4 HR 3.2, 95% CI 2.2-4.6, p=0.0001). Ninety-eight percent (7517/7621) of patients had a preoperative creatinine <200 micromol/l, which is not included as a risk factor in most risk stratification systems. CONCLUSIONS Mild renal dysfunction is an important independent predictor of in-hospital and late mortality in adult patients undergoing cardiac surgery.

Glucose-Insulin-Potassium Reduces the Incidence of Low Cardiac Output Episodes After Aortic Valve Replacement for Aortic Stenosis in Patients With Left Ventricular Hypertrophy

Background— Patients undergoing aortic valve replacement for critical aortic stenosis often have significant left ventricular hypertrophy. Left ventricular hypertrophy has been identified as an independent predictor of poor outcome after aortic valve replacement as a result of a combination of maladaptive myocardial changes and inadequate myocardial protection at the time of surgery. Glucose-insulin-potassium (GIK) is a potentially useful adjunct to myocardial protection. This study was designed to evaluate the effects of GIK infusion in patients undergoing aortic valve replacement surgery. Methods and Results— Patients undergoing aortic valve replacement for aortic stenosis with evidence of left ventricular hypertrophy were randomly assigned to GIK or placebo. The trial was double-blind and conducted at a single center. The primary outcome was the incidence of low cardiac output syndrome. Left ventricular biopsies were analyzed to assess changes in 5′ adenosine monophosphate–activated protein kinase (AMPK), Akt phosphorylation, and protein O-linked &bgr;-N-acetylglucosamination (O-GlcNAcylation). Over a 4-year period, 217 patients were randomized (107 control, 110 GIK). GIK treatment was associated with a significant reduction in the incidence of low cardiac output state (odds ratio, 0.22; 95% confidence interval, 0.10 to 0.47; P=0.0001) and a significant reduction in inotrope use 6 to 12 hours postoperatively (odds ratio, 0.30; 95% confidence interval, 0.15 to 0.60; P=0.0007). These changes were associated with a substantial increase in AMPK and Akt phosphorylation and a significant increase in the O-GlcNAcylation of selected protein bands. Conclusions— Perioperative treatment with GIK was associated with a significant reduction in the incidence of low cardiac output state and the need for inotropic support. This benefit was associated with increased signaling protein phosphorylation and O-GlcNAcylation. Multicenter studies and late follow-up will determine whether routine use of GIK improves patient prognosis. Clinical Trial Registration— URL: http://www.controlled-trials.com. Reference number: ISRCTN 05758301.

Bleeding in cardiac surgery: The use of aprotinin does not affect survival

OBJECTIVE The antifibrinolytic drug aprotinin has been the most widely used agent to reduce bleeding and its complications in cardiac surgery. Several randomized trials and meta-analyses have demonstrated it to be effective and safe. However, 2 recent reports from a single database have implicated the use of aprotinin as a risk for postoperative complications and reduced long-term survival. METHODS In this single-institution observational study involving 7836 consecutive patients (1998-2006), we assessed the safety of using aprotinin in risk reduction strategy for postoperative bleeding. RESULTS Aprotinin was used in 44% of patients. Multivariate analysis identified aprotinin use in risk reduction for reoperation for bleeding (odds ratio, 0.51; 95% confidence interval, 0.36-0.72; P = .001) and need for blood transfusion postoperatively (odds ratio, 0.67; 95% confidence interval, 0.57-0.79; P = .0002). The use of aprotinin did not affect in-hospital mortality (odds ratio, 1.03; 95% confidence interval, 0.71-1.49; P = 0.73), intermediate-term survival (median follow-up, 3.4 years; range, 0-8.9 years; hazard ratio, 1.09; 95% confidence interval, 0.93-1.28; P = .30), incidence of postoperative hemodialysis (odds ratio, 1.16; 95% confidence interval, 0.73-1.85; P = .49), and incidence of postoperative renal dysfunction (odds ratio, 0.78; 95% confidence interval, 0.59-1.03; P = .07). CONCLUSION This study demonstrates that aprotinin is effective in reducing bleeding after cardiac surgery, is safe, and does not affect short- or medium-term survival.

Echocardiography in the Potential Heart Donor

Background. The relationship between echocardiographic left ventricular(LV) systolic function (E-function) and pulmonary artery catheter(PAC) assessment of hemodynamic function (H-function) in potential heart donors is ill defined. We investigated this and determined (a) whether optimization could improve abnormal E-function, (b) feasibility and usefulness of repeat transthoracic echocardiography (TTE), and (c) whether thyroid status and therapy affected E-function. Materials and Methods. Transthoracic E-function imaging was performed at baseline and 4 hr in potential donors (enrolled in a randomized controlled trial of tri-iodothyronine±methylprednisolone [MP] therapy) undergoing PAC-guided algorithmic optimization. Images were analyzed post hoc for LV wall thickness, ejection fraction, and Tei index. Results. The study comprised 66 donors. Both LV ejection fraction (LVEF) and LV-Tei correlated with cardiac index (CI; P<0.001), and LV Tei was most frequently measurable and repeatable(P=0.01). Normal LVEF independently predicted end-assessment H-functional suitability (odds ratio 1.05, 95% confidence interval 1.007–1.088 [P=0.021]) but had poor specificity. Initial subnormal E-function was identified in 29 of 66 of hearts, of which 58% (17/29) achieved H-function suitability criteria. In 52 hearts, repeat E-function assessment was possible. Nineteen of 52 had initially subnormal E-function, which improved in over half (53%). H-function could be manipulated to meet functional suitability criteria for transplant even without E-function change. Neither initial thyroid status nor hormonal therapy affected LV function. Conclusions. Echocardiography is possible in most potential heart donors. Normal E-function predicts hemodynamic suitability for transplantation but lacks specificity. More than 50% of hearts with subnormal E-function can attain hemodynamic transplantation criteria after donor management. Repeat echocardiography is feasible but has a limited role. Both initial echocardiography and PAC-guided management should be used routinely.