Detecting patients with PMI post-CABG based on cardiac troponin-T profiles: A latent class mixed modeling approach.

BACKGROUND: Diagnosis of perioperative myocardial infarction (PMI) after coronary artery bypass grafting (CABG) is fraught with complexity since it is primarily based on a single cut-off value for cardiac troponin (cTn) that is exceeded in over 90% of CABG patients, including non-PMI patients. In this study we applied an unsupervised statistical modeling approach to uncover clinically relevant cTn release profiles post-CABG, including PMI, and used this to improve diagnostic accuracy of PMI. METHODS: In 624 patients that underwent CABG, cTnT concentration was serially measured up to 24 h post aortic cross clamping. 2857 cTnT measurements were available to fit latent class linear mixed models (LCMMs). RESULTS: Four classes were found, described by: normal, high, low and rising cTnT release profiles. With the clinical diagnosis of PMI as golden standard, the rising profile had a diagnostic accuracy of 97%, compared to 83% for an optimally chosen cut-off and 21% for the guideline recommended cut-off value. CONCLUSION: Clinically relevant subgroups, including patients with PMI, can be uncovered using serially measured cTnT and a LCMM. The LCMM showed superior diagnostic accuracy of PMI. A rising cTnT profile is potentially a better criterion than a single cut-off value in diagnosing PMI post-CABG.

Postoperative conduction disorders after implantation of the self-expandable sutureless Perceval S bioprosthesis.

BACKGROUND AND AIM OF THE STUDY: Minimally invasive techniques for aortic valve replacement (AVR) have been developed as an alternative to conventional AVR for patients with high operative risk. Yet, these techniques are still associated with an increased risk of postoperative conduction disorders. The study aim was to identify the incidence and fate of postoperative conduction disorders in patients undergoing sutureless (SU) AVR with the Perceval S bioprosthesis. METHODS: In this observational study, patients who underwent SU AVR with the Perceval S prosthesis at the Catharina Hospital, Eindhoven, were analyzed. Electrocardiograms (ECGs) recorded at baseline, within 24 h postoperatively, before hospital discharge and at follow up were collected by reviewing patients' records. The ECGs were analyzed by two independent investigators to record QRS-duration and conduction disorders. RESULTS: All patients (n = 31) who underwent implantation of the Perceval S bioprosthesis between September 2010 and September 2012 were included. At baseline, three patients (9.7%) had preexisting left bundle branch block (LBBB), and one patient (3.2%) had a permanent pacemaker (PPM). New-onset LBBB developed in 11 patients (39.3%), and was transient in three patients (10.7%). Postoperatively, four patients (13.3%) required PPM implantation because of total atrioventricular block; all of these patients had either pre-existing LBBB (n = 1) or new LBBB (n = 3). CONCLUSION: Sutureless AVR with the Perceval S bioprosthesis was frequently complicated by new LBBB, which was persistent in the majority of patients. A relatively high incidence of postoperative PPM implantation was also observed.

Does the body mass index predict mortality after isolated aortic valve replacement?

BACKGROUND AND AIM OF THE STUDY: Data relating to the impact of body mass index (BMI) on outcomes after isolated aortic valve replacement (AVR) are scarce and controversial. The study aim was to investigate the predictive value of BMI for early and late mortality after isolated AVR. METHODS: Data obtained from patients who underwent isolated AVR between January 1998 and December 2010 at the authors' institution were analyzed retrospectively. Patients were allocated to five groups according to the preoperative BMI: underweight (BMI < 20 kg/m2); normal weight (BMI 20.0-24.9 kg/m2); overweight (BMI 25.0-29.9 kg/m2); obese (BMI 30.0-34.9 kg/m2); and morbidly obese (BMI > 34.9 kg/m2). Logistic and Cox regression analyses were performed to identify the independent predictors of early and late mortality, respectively. RESULTS: After excluding 20 patients who were lost to follow up, and 30 patients with missing preoperative BMI data, a total of 1,758 patients was included in the analysis. The mean follow up was 5.6 +/- 3.5 years (range: 0-13.4 years), and the mean BMI 26.8 +/- 4.3 kg/m2 (range: 17-52 kg/m2). Multivariate logistic regression analyses showed no association between early mortality and the BMI groups. Multivariate Cox regression analyses showed 'underweight' to be an independent predictor for late mortality (hazard ratio 2.89; 95% confidence interval 1.63-5.13, p < 0.0001). CONCLUSION: 'Underweight' is an independent predictor for late mortality after AVR surgery. Morbid obesity did not prove to be predictive of a worse late survival.

Does removal of steel wires relieve post-sternotomy pain after cardiac surgery?

BACKGROUND: Post-sternotomy pain in the absence of cardiac ischemia and sternal instability is most commonly due to the sternal wire sutures or a protruding wire. We performed a retrospective study to investigate the effect of removal of the steel wires for relief of post-sternotomy pain. METHODS: All 206 patients who underwent sternal wire removal in our institution from January 2003 through August 2011 were included in this study. Alive patients were contacted by telephone to inquire about the fate of their pain. Accordingly, patients were classified into 4 groups: group 1 were free of symptoms; group 2 were satisfied, significantly better than before wire removal; group 3 had unchanged symptoms; and group 4 had worsening of pain after wire removal. RESULTS: After excluding patients who died during the follow-up and those who had sternal instability and wound infection, 186 patients were available for the questionnaire. Complete relief of pain occurred in 83% of these patients, and 10% had improvement of their symptoms. CONCLUSIONS: We recommend removal of the steel wires in patients with persistent chest pain after median sternotomy, when sternal instability, mediastinitis, and cardiac causes such as ischemia are excluded.

Results of one-hundred and seventy patients after elective Bentall operation.

The aim of this study was to evaluate the short and long-term operative results of patients who underwent a Bentall procedure in a 12-year period. We retrospectively analyzed the data of 170 patients who underwent an elective Bentall procedure between January 1998 and July 2010. All pre- and perioperative variable were entered into a multivariate regression model to identify significant predictors of early and late mortality. The early mortality rate was 11.2% (19/170 patients). Multivariate logistic regression analysis identified prior cardiac operation and cardiopulmonary bypass time as independent risk factors for early mortality, with odds ratios of 5.75 (95% confidence interval: 1.850-17.874; p=0.003) and 1.011 (95% confidence interval: 1.003-1.019; p=0.008), respectively. The Kaplan-Meier curve shows an overall survival of 78%±4% at 5 years and 66%±10% at 10 years. Cox regression analysis revealed no independent risk factors for late mortality. The Bentall procedure is still the procedure of choice for aortic root replacement. Improvements in perioperative management in recent years has improved the early outcome, and in our experience, the late results of this technique were satisfactory.

Prophylactic treatment with alkaline phosphatase in cardiac surgery induces endogenous alkaline phosphatase release.

INTRODUCTION: Laboratory and clinical data have implicated endotoxin as an important factor in the inflammatory response to cardiopulmonary bypass. We assessed the effects of the administration of bovine intestinal alkaline phosphatase (bIAP), an endotoxin detoxifier, on alkaline phosphatase levels in patients undergoing coronary artery bypass grafting. METHODS: A total of 63 patients undergoing coronary artery bypass grafting were enrolled and prospectively randomized. Bovine intestinal alkaline phosphatase (n=32) or placebo (n=31) was administered as an intravenous bolus followed by continuous infusion for 36 hours. The primary endpoint was to evaluate alkaline phosphatase levels in both groups and to find out if administration of bIAP to patients undergoing CABG would lead to endogenous alkaline phosphatase release. RESULTS: No significant adverse effects were identified in either group. In all the 32 patients of the bIAP-treated group, we found an initial rise of plasma alkaline phosphatase levels due to bolus administration (464.27±176.17 IU/L). A significant increase of plasma alkaline phosphatase at 4-6 hours postoperatively was observed (354.97±95.00 IU/L) as well. Using LHA inhibition, it was shown that this second peak was caused by the generation of tissue non specific alkaline phosphatase (TNSALP-type alkaline phosphatase). CONCLUSIONS: Intravenous bolus administration plus 8 hours continuous infusion of alkaline phosphatase in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass results in endogenous alkaline phosphatase release. This endogenous alkaline phosphatase may play a role in the immune defense system.

Right atrial thrombus migrating to the superior vena cava during surgery.

Free-floating right heart thrombi are extremely mobile structures that carry a very high mortality rate. We describe a case of pulmonary embolism with a free-floating right heart thrombus that migrated to the superior vena cava during the institution of cardiopulmonary bypass.

Coronary ischemia due to subclavian stenosis after arterial revascularization.

We describe a case of coronary-subclavian steal in a 60-year-old man who presented with progressive ischemia 16 years after coronary artery bypass with in-situ bilateral internal thoracic artery grafts. Angiography revealed completely patent arterial grafts, but subtotal stenosis of the left subclavian artery. On reoperation, a vein graft was used to connect the aorta to the left internal thoracic artery which was proximally disrupted. No coronary ischemia was found postoperatively.

Thrombocytopenia after aortic valve replacement: comparison between mechanical and biological valves.

BACKGROUND AND AIM OF THE STUDY: Concerns have been recently raised regarding the postoperative decrease in platelet count after aortic valve replacement (AVR). Thus, a retrospective analysis was conducted of patients after AVR with regards to postoperative platelet count. METHODS: The data were analyzed from all patients undergoing AVR with (n = 829) or without (n = 1,230) coronary artery bypass grafting (CABG) at a single center between January 1998 and May 2009. The lowest (minimum) platelet count within the first five postoperative days was determined. RESULTS: The patients received either an ATS mechanical prosthesis (ATS; n = 401), a St. Jude Medical mechanical prosthesis (SJM; n = 791), a Carpentier-Edwards Perimount bioprosthesis (CEP; n = 618), a Medtronic Freestyle stentless bioprosthesis (FRE; n = 213), or a Sorin Freedom Solo stentless bioprosthesis (SFS; n = 36). By using a multivariate linear regression model, the following independent risk factors for a lower postoperative platelet count were revealed: age, body surface area, active endocarditis, preoperative platelet count, duration of extracorporeal circulation, number of grafts, valve size, and units of transfused fresh-frozen plasma and red blood cells. On entering the type of prosthesis into the multivariate linear regression analysis, together with the other risk factors, patients with CEP and FRE valve prostheses had a lower minimum postoperative platelet count than those with mechanical prostheses (ATS and SJM). CONCLUSION: Patients undergoing AVR with the Carpentier-Edwards Perimount bioprosthesis or a Medtronic Freestyle stentless bioprosthesis had a lower minimum platelet count within the first five postoperative days, compared to patients receiving ATS and St. Jude Medical mechanical prostheses. No differences were identified between the Sorin Freedom Solo and all other valve prostheses.

Preoperative ejection fraction as a predictor of survival after coronary artery bypass grafting: comparison with a matched general population.

BACKGROUND: Preoperative left ventricular dysfunction is an established risk factor for early and late mortality after revascularization. This retrospective analysis demonstrates the effects of preoperative ejection fraction on the short-term and long-term survival of patients after coronary artery bypass grafting. METHODS: Early and late mortality were determined retrospectively in 10 626 consecutive patients who underwent isolated coronary bypass between January 1998 and December 2007. The subjects were divided into 3 groups according to their preoperative ejection fraction. Expected survival was estimated by comparison with a general Dutch population group described in the database of the Dutch Central Bureau for Statistics. For each of our groups with a known preoperative ejection fraction, a general Dutch population group was matched for age, sex, and year of operation. RESULTS AND DISCUSSION: One hundred twenty-two patients were lost to follow-up. In 219 patients, the preoperative ejection fraction could not be retrieved. In the remaining patients (n = 10 285), the results of multivariate logistic regression and Cox regression analysis identified the ejection fraction as a predictor of early and late mortality. When we compared long-term survival and expected survival, we found a relatively poorer outcome in all subjects with an ejection fraction of < 50%. In subjects with a preoperative ejection fraction of > 50%, long-term survival exceeded expected survival. CONCLUSIONS: The severity of left ventricular dysfunction was associated with poor survival. Compared with the survival of the matched general population, our coronary bypass patients had a worse outcome only if their preoperative ejection fraction was < 50%.

Is the use of Steri-StripTM S for wound closure after coronary artery bypass grafting better than intracuticular suture?

Several methods have been used in wound closure after coronary artery bypass grafting (CABG). In this study, the safety and efficacy of one of these methods, Steri-Strip S is compared with the traditional intracuticular suture method. Eighty-one patients undergoing CABG were prospectively randomized into two groups according to the method of skin closure: Steri-Strip S group and traditional suture group. Comparison between the two methods was done with regards to the length of the wound and the time needed to close it. The median closure time with Steri-Strip S was 5.45+/-3.35 min vs. 7.53+/-3.41 min in the suture group. A pain score of >or=6 at the first postoperative day was found in 30% of the patients in the suture group vs. 14% of the patients in the Steri-Strip S group (P=0.07). Cosmetic evaluation showed a non-significant difference in the linear visual analogue score in favor of Steri-Strip S group compared to the intracuticular suture group (73.1 vs. 70.1) (P=0.07). Steri-Strip S is a fast, safe alternative for wound closure of the sternotomy incision and graft harvesting site. A larger study is needed to establish the potential beneficial effect of Steri-Strip S on wound infection prevention.

Risk factors for deterioration of renal function after coronary artery bypass grafting.

OBJECTIVE: Various definitions of impairment of renal function after coronary artery bypass grafting (CABG) are used in the literature. Depending on the definition, several risk factors are identified. We analysed our data to determine the risk factors for postoperative deterioration of the creatinine clearance of 10% or more. METHODS: All patients undergoing isolated coronary surgery in a single centre between January 1998 and December 2007 are included. Clinical data, including demographics and renal risk factors, were prospectively collected in our database. The most recent preoperative serum creatinine level and the maximum serum creatinine level within the first week postoperatively were used to calculate the creatinine clearance. A deterioration of 10% or more was considered to be an endpoint for this study. RESULTS: In 10098 out of a total of 10626 patients, the preoperative as well as the postoperative creatinine clearance could be calculated. In 1053 patients, the deterioration of the creatinine clearance was 10% or more. We could identify the following risk factors: advanced age, diabetes, chronic obstructive pulmonary disease, peripheral vascular disease, emergency operation, previous cardiac surgery, low preoperative haemoglobin level, high preoperative C-reactive protein level, perioperative myocardial infarction, re-exploration and the number of blood transfusions. CONCLUSIONS: Risk factors for the deterioration of renal function after revascularisation have been confirmed in this study. In addition, we found peripheral vascular disease, previous cardiac surgery, low preoperative haemoglobin, increased preoperative C-reactive protein level, perioperative myocardial infarction and the number of blood transfusions to be risk factors that have not been described earlier.

Acute hemodynamic effects of cardiac resynchronization therapy in patients with poor left ventricular function during cardiac surgery.

BACKGROUND: Cardiac resynchronization therapy improves systolic function in patients with heart failure and left ventricular (LV) dyssynchrony. However, the effect of biventricular (BiV) pacing on perioperative hemodynamics in cardiac surgery is not well known. We investigated the acute hemodynamic response using LVdP/dt(max) in patients with depressed LV function and conduction disturbances undergoing cardiac surgery. METHODS: Patients with LV ejection fraction of < or =35%, QRS duration of >130 ms, and left bundle branch block undergoing aortocoronary bypass and valve surgery were included. Temporary atrial and left and right ventricular pacing wires were applied, and LVdP/dt(max) was measured with a high fidelity pressure wire in the left ventricle at the end of cardiopulmonary bypass. Responders had a > or =10% increase in LVdP/dt(max). RESULTS: Eleven patients (age 63 +/- 11 years, eight males) with a LV ejection fraction 0.29 +/- 0.06% were included. Compared with right ventricular pacing (782 +/- 153 mmHg/sec), there was a significant improvement in the mean LVdP/dt(max) during simultaneous BiV pacing (849 +/- 174 mmHg/sec; p = 0.034) and sequential BiV pacing with the LV 40 ms advanced (880 +/- 157 mmHg/sec; p = 0.003). Improvement during LV pacing alone was not significant (811 +/- 141 mmHg/sec). Six patients were responders with simultaneous and nine with sequential BiV pacing. Only sequential BiV pacing had a significant improvement in LV systolic pressure (p = 0.02). CONCLUSIONS: BiV pacing results in acute hemodynamic improvement of LV function during cardiac surgery. Optimization of the interventricular pacing interval contributes to the effect of the therapy.

Preoperative hemoglobin level as a predictor of survival after coronary artery bypass grafting: a comparison with the matched general population.

BACKGROUND: The predictive value of the preoperative hemoglobin value after coronary artery bypass grafting (CABG) has not been well established. We studied how the preoperative hemoglobin level affects the survival of patients after CABG. Late mortality was compared with that of a general population. METHODS AND RESULTS: Early and late mortality of all consecutive patients undergoing isolated CABG between January 1998 and December 2007 were determined. Patients were classified into 4 groups stratified by preoperative hemoglobin level. The cutoff point for anemia was 13 g/dL for men and 12 g/dL for women. Expected survival of a matched general Dutch population cohort was obtained from the database of the Dutch Central Bureau for Statistics. After the exclusion of 122 patients who were lost to follow-up and 481 patients with missing preoperative hemoglobin levels, complete data were obtained in 10,025 patients. Multivariate logistic regression analyses revealed anemia to be an independent risk factor for higher early mortality. Cox regression analyses revealed low hemoglobin level, both as a continuous variable and as a dichotomous variable (anemia), to be a predictor of higher late mortality. Compared with expected survival, patients with the lowest preoperative hemoglobin levels had a worse outcome, whereas patients with the highest hemoglobin levels had a better outcome. CONCLUSIONS: A lower preoperative hemoglobin level is an independent predictor of late mortality in patients undergoing CABG, whereas anemia is a risk factor for early and late mortality. Compared with the general population, anemic patients had worse survival than expected, whereas nonanemic patients had better survival than expected.

Anti-inflammatory effects of alkaline phosphatase in coronary artery bypass surgery with cardiopulmonary bypass.

Laboratory and clinical data have implicated endotoxin as an important factor in the inflammatory response to cardiopulmonary bypass. Alkaline phosphatase prevents endotoxin-induced systemic inflammation in animals and humans. We assessed the effects of the administration of bovine intestinal alkaline phosphatase on surgical complications in patients undergoing coronary artery bypass grafting. In a double blind, randomized, placebo-controlled study, a total of 63 patients undergoing coronary artery bypass grafting were enrolled. Bovine intestinal alkaline phosphatase or placebo was administered as an intravenous bolus followed by continuous infusion for 36 hours. The primary endpoint was reduction of post-surgical inflammation. No significant safety concerns were identified. The overall inflammatory response to coronary artery bypass grafting with cardiopulmonary bypass was low in both placebo and bovine intestinal alkaline phosphatase patient group. Five patients in the placebo group displayed a significant TNFalpha response followed by an increase in plasma levels of IL-6 and IL-8. Such a TNFalpha response was not observed in the bovine intestinal alkaline phosphatase group, suggesting anti-inflammatory activity of bovine intestinal alkaline phosphatase. Other variables related to systemic inflammation showed no statistically significant differences. Bovine intestinal alkaline phosphatase can be administered safely in an attempt to reduce the inflammatory response in coronary artery bypass grafting patients with a low to intermediate EuroSCORE. The anti-inflammatory effects might be more pronounced in patients developing more fulminant postoperative inflammatory responses. This will be investigated in a further trial with inclusion of patients undergoing complicated cardiac surgery, demanding extended cardiopulmonary bypass and aortic cross clamp time. In this review article some recent patents related to the field are also discussed.