Microbiological Spectrum of Nosocomial ECMO Infections in a Tertiary Care Center

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) is a life-saving treatment in cardiogenic and respiratory shock. It is prone to various complications, infection being among the most frequent. This study aims to define the prevalence and characteristics of infections in ECMO patients in a tertiary care center for cardiac diseases.

METHODS

All ECMO patients between 2012 and 2016 in a single cardiac center were retrospectively included. Demographic data, ECMO indications, type, site, duration, and infection-related data were recorded. Data were analyzed among all patients and separately between pediatric and adult patient groups.

RESULTS

One hundred and twenty-six patients, 66 (53.4%) pediatric and 60 (47.6%) adult, received ECMO within the study period. Mean age was 3.54±4.27 years in the pediatric group and 54.92±15.57 years in the adult group. The main indication for ECMO was postcardiotomy shock (77.8%). Forty-six (36.5%) of all cases developed a culture-proven nosocomial infection with a rate of 49/1000 ECMO days. Infection was associated with > 5 days of ECMO duration and hemodialysis requirement in all patients and lower age in the pediatric group. The most frequent infection site was the lower respiratory tract (14.3%), while the most common isolated organisms were Klebsiella (8.7%) and Streptococcus (4.8%) species.

CONCLUSION

The respiratory tract is the most common site of infection, however, all sites impose a threat to recovery, with longer treatment durations required for patients with culture-proven infections. A better understanding of the infectious spectrum and its effect on the mortality and morbidity is required for more successful treatment of ECMO patients.

Risk factors for vasoplegia after coronary artery bypass and valve surgery

INTRODUCTION

Vasoplegia denotes a state of low tissue perfusion characterized by hypotension, tachycardia, and low systemic vascular resistance. This state results in increased mortality and morbidity following cardiac surgery. A better understanding of the associated risk factors will guide the surgical team in patient management. The aim of this study is to determine which risk factors are involved in its emergence.

METHODS

This prospective observational study included adult cardiac surgery patients between February - September 2018 at a single cardiothoracic surgery center. Patients were evaluated for cardiac contractility, surgical drainage, inotrope, and vasopressor requirement perioperatively. The groups were compared for demographic, echocardiographic, and operative variables. Variables significant in univariate analysis were carried on to binary logistic regression for risk factor analysis.

RESULTS

A total of 31 patients were vasoplegic among a total of 487 included patients, resulting in a 6.37% incidence. In the vasoplegia group, chronic kidney failure, use of angiotensin-converting enzyme (ACE) inhibitors, use of angiotensin receptor blockers, and use of diuretics were more frequent, cardiopulmonary bypass (CPB) and aortic cross-clamp durations were longer, and mean Euroscore II was higher. Vasoplegia was more frequent in valve surgery and resternotomy patients. CPB duration, use of ACE inhibitors, use of angiotensin receptor blockers, and chronic renal failure were independent risk factors.

CONCLUSION

Patients with long CPB duration, preoperative use of ACE inhibitors or Angiotensin receptor blockers, and a history of renal failure requiring dialysis are under increased risk of vasoplegia. Vasoplegia necessitates large-scale studies for a better understanding of its risk factors.

Pressure-dimension index: A novel "morphologic-functional" index of right ventricle that predicts short-term survival after left ventricular assist device implantation

BACKGROUND

Right ventricular failure (RVF) after left ventricular assist device (LVAD) implantation is a major cause of postoperative morbidity and mortality. Despite the availability of multiple imaging parameters, none of these parameters had adequate predictive accuracy for post-LVAD RVF.

AIM

To study whether right ventricular pressure-dimension index (PDI), which is a novel echocardiographic index that combines both morphologic and functional aspects of the right ventricle, is predictive of post-LVAD RVF and survival.

METHODS

49 cases that underwent elective LVAD implantation were retrospectively analyzed using data from an institutional registry. PDI was calculated by dividing systolic pulmonary artery pressure to the square of the right ventricular minor diameter. Cases were categorized according to tertiles.

RESULTS

Patients within the highest PDI tertile (PDI>3.62 mmHg/cm² ) had significantly higher short-term mortality (42.8%) and combined short-term mortality and severe RVF (50%) compared to other tertiles (P < .05 for both, log-rank p for survival to 15th day 0.014), but mortality was similar across tertiles in the long-term follow-up. PDI was an independent predictor of short-term mortality (HR:1.05-26.49, P = .031) and short-term composite of mortality and severe RVF (HR:1.37-38.87, P = .027).

CONCLUSIONS

Increased PDI is a marker of an overburdened right ventricle. Heart failure patients with a high PDI are at risk for short-term mortality following LVAD implantation.

Usefulness of right ventricular contraction pressure index to predict short-term mortality and right heart failure in patients who underwent continuous-flow left ventricular assist device implantation

Background:

Right ventricular stroke work index is a useful but invasively measured parameter that can be used to predict right heart failure following continuous-flow left ventricular assist device implantation. Right ventricular contraction pressure index is a novel parameter that was developed to measure right ventricular stroke work index with echocardiography. We aimed to investigate the clinical usefulness of right ventricular contraction pressure index to predict short-term mortality and right heart failure in patients who underwent continuous-flow left ventricular assist device implantation.

Methods:

A total of 49 patients who participated in institutional advanced heart failure registry and underwent continuous-flow left ventricular assist device implantation with a bridge-to-candidacy indication were analyzed retrospectively. Right ventricular contraction pressure index was calculated using offline measurements. Demographic, clinical and outcome data were obtained from the registry data. Patients were grouped according to right ventricular contraction pressure index quartiles.

Results:

Patients within the lowest right ventricular contraction pressure index quartile had a trend toward higher short-term mortality (46.2%, p = 0.056) and combined short-term mortality and definitive right heart failure (53.8%, p = 0.054) at 15th day postoperatively. Similarly, short-term survival or survival free of definite right heart failure were significantly lower in the lowest right ventricular contraction pressure index quartile (log-rank p = 0.045 and log-rank p = 0.03, respectively). In a proportional hazards model that included echocardiographic parameters, right ventricular contraction pressure index was an independent predictor for short-term mortality (odds ratio: 6.777, 95% confidence interval: 1.118–41.098, p = 0.037), but not for combined short-term mortality and definite right heart failure. No such associations were found for long-term mortality. Right ventricular contraction pressure index had a statistically significant correlation with invasively measured pulmonary capillary wedge pressure, pulmonary vascular resistance, mean pulmonary pressure, and right ventricular stroke work index.

Conclusion:

Right ventricular contraction pressure index was found as a useful parameter for determining short-term postoperative mortality in patients undergoing continuous-flow left ventricular assist device implantation.

The importance of mass diameter in decision-making for preoperative coronary angiography in myxoma patients

OBJECTIVES

Although coronary angiography (CAG) is generally performed to rule out coexisting coronary artery disease in patients with cardiac myxoma, its necessity to evaluate vascular supply of the myxoma is debatable. The aim of this article is to evaluate clinical experience and CAG findings in our patient group.

METHODS

This retrospective analysis was performed in 46 patients (17 men, mean age 57.7 ± 8.6 years), who underwent surgery with an indication for cardiac myxoma between 2004 and 2016 with a CAG performed preoperatively. All CAGs were evaluated in a blinded manner by a cardiac surgeon and a cardiologist separately. Correlations between the presence and pattern of feeding vessels, presence of an arteriocavity fistula (ACF), coronary arterial dominance, size of mass and clinical presentations were analysed.

RESULTS

Coronary artery disease defined as >50% obstructive lesions was detected in 10 patients (21.7%). The tumour diameter was found to be significantly higher in patients who had an ACF and a dual-feeding artery (P = 0.049 and P = 0.0001, respectively). Additionally, there was a significant relationship between the presence of dual-feeding vessels and ACF (P = 0.014). ROC analysis revealed a cut-off point of 27 mm in diameter based on the presence of an ACF and a dual-feeding artery. In cases with a diameter of 27 mm or above, the risk of existence of an ACF was 4.68-fold greater, with a confidence interval of 95%, and a dual-feeding pattern was seen in all of them.

CONCLUSIONS

This study suggests that preoperative CAG can be considered to detect feeding vessels that may lead to a steal phenomenon, which may alter the management in patients with myxoma greater than 27 mm in diameter.

Retrospective cohort study for evaluating the INR monitoring patterns in patients with deep vein thrombosis in daily practice: Analysis of 2010-2013 database of a tertiary care center

OBJECTIVE

To evaluate the international normalized ratio (INR) monitoring patterns in patients with deep vein thrombosis.

METHODS

Of 32,012 patients with ≥1 outpatient INR measurement and 42,582 patients with confirmed deep vein thrombosis diagnosis registered to our hospital between 1 January 2010 and 31 December 2013, 6720 records were identified to have both deep vein thrombosis and international normalized ratio measurement, and 4.377 out of 6.720 single patient records were determined to be statistically analyzable.

RESULTS

Median INR measurement frequency was 6.47 times/year and patients had INR levels of 2-3 in 34.3% of follow-up time. Having ≥70% vs. <70% of follow-up time within therapeutic range was associated with lower hospital admission frequency (9.7 vs. 10.3 times/year).

CONCLUSION

Our study revealed only one-third of the follow-up time to be spent within therapeutic INR, association of INR therapeutic range with lesser number of hospital admissions and INR monitoring frequency of 6.47 times/year despite lack of stable INR control in most of the deep vein thrombosis patients.

Long term outcomes of surgical revascularization for isolated left main coronary artery stenosis: a single-center surveillance study

OBJECTIVE

The objective of this study was to retrospectively analyze the clinical course and postoperative long-term survival of patients diagnosed with isolated left main coronary artery (LMCA) stenosis after surgical revascularization.

METHODS

A total of 38 patients (27 males, 11 females) who were diagnosed with isolated LMCA stenosis and underwent surgical revascularization were enrolled in the study. Isolated LMCA stenosis was classified into 2 groups: ostial stenosis and nonostial stenosis. Coronary events were defined as death of cardiac origin, the need for a new myocardial revascularization procedure, or the occurrence of myocardial infarction in the course of follow-up. The postoperative assessment period included short- and long-term follow-up. The study endpoint was defined as all-cause mortality.

RESULTS

Among the 38 patients who participated in the study, 25 suffered from ostial LMCA stenosis. The early postoperative mortality rate before hospital discharge was 2.6%. Median duration of postoperative long-term follow-up was 73.43 months (range: 0.17-187.23). Median duration of long-term follow-up free from coronary events or percutaneous coronary interventions was 73.43 months. Postoperative 2-year survival rate was 97.4%, and 5-year survival rate was 92.1%. The postoperative survival period and period free of coronary events of patients with isolated ostial LMCA stenosis did not differ significantly from those of patients with nonostial stenosis (p=0.801, p=0.970, respectively).

CONCLUSION

Postoperative short- and long-term prognosis of isolated LMCA stenosis appears good in terms of mortality and coronary event symptoms.

Preoperative risk factors for in-hospital mortality and validity of the Glasgow aneurysm score and Hardman index in patients with ruptured abdominal aortic aneurysm

The aim of this study is to evaluate the validity of the Glasgow aneurysm score (GAS) and Hardman index in patients operated on because of ruptured abdominal aortic aneurysm (rAAA), and determining preoperative risk factors that affect in-hospital mortality. One hundred one patients operated on to repair a rAAA within the last 10 years were included. The GAS and Hardman index were calculated for each patient separately. The relation between in-hospital mortality and the Hardman index and GAS was analyzed by means of the receiver-operator characteristic (ROC) curve. Univariate and multivariate methods of analyses were used to determine preoperative risk factors. Average age was 69 ± 8, and in-hospital mortality rate was 51.5%. Analysis of the ROC curve showed that the Hardman index had an area under the curve (AUC) = 0.71 (95% confidence interval [CI], 0.593–0.800, P = 0.0002) for predicting in-hospital mortality. The GAS had an AUC = 0.77 (95% CI, 0.680–0.851, P < 0.0001). The results of multivariate analysis revealed the presence of the following preoperative risk factors: age more than 63 years (odds ratio [OR], 4.4; 95% CI, 1.17–16.49, P = 0.028); loss of consciousness (OR, 9.33; 95% CI, 1.94–44.86, P = 0.005); creatinine higher than 1.7 mg/dL (OR, 5.52; 95% CI, 1.92–15.85, P = 0.001); and pH lower than 7.31 (OR, 3.77; 95% CI, 1.18–11.99, P = 0.024). In conclusion, the Hardman index and GAS have a significant correlation with in-hospital mortality rates. Nevertheless, a high score does not necessarily correspond with a definite mortality. This is why scoring systems could not be considered as the sole criterion for choosing patients for this study. Clinical experience was still the leading factor in deciding against or in favor of surgery.

Emergency management for critical left main coronary artery stenosis

BACKGROUND

Increased experience and improvements in technology seem to have encouraged the use of percutaneous interventions for left main coronary artery (LMCA) occlusions. There is no consensus, however, and the data are inadequate on whether surgery or percutaneous procedures should be the intervention of choice for critical occlusions.

METHODS

From January 2002 to December 2006, 108 patients with unprotected LMCA stenosis >80% were treated at our center. Eighty-three patients (77%) underwent bypass grafting and 20 (18%) underwent percutaneous intervention for the purpose of myocardial revascularization. We analyzed parameters demonstrated as risk factors for myocardial revascularization and their predicted effects on outcome.

RESULTS

Five patients (5%) died following emergency cardiopulmonary resuscitation before any intervention was performed. The early survival rate was 84.1% in the coronary bypass group and 63% in the percutaneous intervention group. The mean (±SD) survival time was 55.7 ± 2.6 months in the bypass group and 7.6 ± 1.3 months in the percutaneous group. The late-survival rate was also significantly higher in the bypass group. The mean late-survival time was 44.5 ± 3.6 months in the bypass group and 2.3 ± 0.8 months in the percutaneous group.

CONCLUSION

Although emergency percutaneous interventions are lifesaving in some cases, these results clearly demonstrate that coronary bypass grafting should be the intervention of choice for myocardial revascularization in patients with critical LMCA occlusion.

Effects of N-acetylcysteine on myocardial ischemia-reperfusion injury in bypass surgery

Myocardial ischemia-reperfusion injury may complicate coronary artery bypass grafting (CABG) operations. N-Acetylcysteine (NAC) had antioxidant and microcirculatory effects, and inhibits neutrophil aggregation. The aim of this study was to determine the effects of NAC in limiting myocardial ischemia-reperfusion injury in CABG operations. Twenty patients undergoing elective coronary bypass operation with cardiopulmonary bypass were enrolled and randomly assigned to two groups: a control group operated with a routine CABG protocol, and one where NAC was administered intravenously during the operation (NAC group). Blood samples from coronary sinus for tumor necrosis factor-alpha assay, myocardial biopsy specimens for chemiluminescent luminol, and lucigenin measurements of reactive oxygen species were taken. The luminol (specific for (*)OH, H(2)O(2), and HOCl(-) radicals) and lucigenin (specific for O(2) (*-)) levels and the difference ratios after reperfusion were significantly lower in the NAC group. Tumor necrosis factor-alpha levels increased in the control group but, in contrast, a significant decrease was detected in the NAC group (P < 0.01). Creatine kinase-MB levels at 6 and 12 hours were significantly lower in the NAC group (P = 0.02). N-Acetylcysteine has potential effects to limit ischemia reperfusion injury during CABG operations. We believe that its effects on clinical outcome may be more apparent in patients prone to ischemia-reperfusion injury.

Systemic and myocardial inflammation in traditional and off-pump cardiac surgery

In this study, we attempted to determine the role of off-pump coronary artery bypass grafting (CABG) in the myocardial and systemic inflammatory responses. Twenty patients who underwent elective CABG were enrolled in this study. Ten patients underwent on-pump CABG, and 10 patients underwent off-pump CABG. There were no differences between patients in preoperative clinical variables. We took systemic venous blood samples for the measurement of tumor necrosis factor-alpha, the MB isoenzyme of creatine kinase (CK-MB), and cardiac troponin I, and we took myocardial biopsies from the interventricular septum for chemiluminescence assay of reactive oxygen species (hydroxyl, hydrogen peroxide, hypochlorite, and superoxide). There was no significant difference in the myocardial tissue release of hydrogen peroxide, hydroxyl, hypochlorite, and superoxide between the 2 groups (P > 0.05). The systemic tumor necrosis factor-alpha levels in the off-pump group were significantly lower than in the on-pump group (P <0.01). The cardiac troponin I and creatine kinase-MB levels at 6, 12, and 24 postoperative hours were not statistically different between the 2 groups (P >0.05). We conclude that off-pump CABG appears to reduce systemic inflammation, without reducing myocardial oxidative stress and inflammation.

Functional Results in Aortic Root Enlargement

BACKGROUND

The hemodynamically efficient valves with effective orifice areas that are used in aortic valve replacement have been positively determined to affect postoperative exercise capacity. The aim of this study was to evaluate the functional effects of aortic root enlargement in the late postoperative period for patients with a small effective orifice area.

METHODS

Nineteen patients with a small effective orifice area were included in the study. The study group comprised 9 patients who underwent isolated aortic valve replacement with 23-mm St. Jude Medical prosthetic valves and posterior aortic root enlargement. The control group comprised 10 patients in whom 19-mm and 21-mm St. Jude Medical prosthetic valves were implanted without aortic root enlargement. The patients were evaluated in the late postoperative period with echocardiography and cardiopulmonary exercise testing.

RESULTS

The 2 groups were similar in anthropometric parameter values, follow-up periods, echocardiographic findings, and the gradients at the prosthetic aortic valve at rest; however, the anaerobic threshold, peak oxygen uptake, minute ventilation volume, and walk time were significantly higher in the study group ( P <.05).

CONCLUSION

The choice of aortic root enlargement for the implantation of a valve with a larger effective orifice area is preferred by most of the surgeons over the implantation of a valve with a smaller effective orifice area. The late postoperative functional capacity of the patient is significantly improved with root enlargement. Surgeons should be encouraged to perform root enlargement in patients with a small effective orifice area, and such surgery may even be performed routinely in these patients.

Coronary artery bypass graft operations can be performed safely in obese patients

OBJECTIVES

Obesity is a major public health problem with an increasing prevalence. Although coronary artery bypass grafting (CABG) operations are now performed with low morbidity and mortality rates, obesity is still assumed to be an important risk factor for morbidity and mortality at these operations but there is no precise approach to define it as a risk factor. The aim of this study is to evaluate the effects of obesity on the clinical outcome of the CABG operations.

METHODS

A total of 1206 patients, who underwent isolated CABG operation under cardiopulmonary bypass were evaluated retrospectively. The patients were divided into three groups. Group I was normal weight, with body mass index (BMI) of 18-24.9 kg/m(2), group II was overweight, with a BMI of 25-29.9 kg/m(2), and group III was obese, with a BMI of >30 kg/m(2). The clinical data of three groups were evaluated in aspects of postoperative morbidity and mortality.

RESULTS

Except for the superficial wound infections, there were no differences in postoperative mortality and morbidity rates between the three groups. Obesity was not found to be an important risk factor for postoperative morbidity and mortality.

CONCLUSIONS

Despite the perception that obesity increases the risk of mortality and morbidity in CABG operations, the clinical outcome of these patients are not so different from other patients. We may say that obese patients can be safely operated.

Ultrasonic decalcification of calcified valve and annulus during heart valve replacement

A heavily calcified heart valve annulus increases the likelihood of sequelae after prosthetic valve replacement. Such sequelae include cerebral embolism, paravalvular leakage, valvular dysfunction, rhythm disturbance, hemolysis, communication of the heart chambers, and rupture of the posterior wall of the left ventricle. From January 1991 through June 1994, we performed heart valve replacement on 30 patients, using an ultrasonic surgical aspirator to remove calcific deposits. We placed aortic valve prostheses in 12 patients, mitral valve prostheses in 13 patients, and both aortic and mitral prostheses in 5 patients, after ultrasonic débridement of calcified annuli. All patients were re-examined 6 months after surgery: echocardiographic study showed no paravalvular leakage or valve-related complications. In our experience, ultrasonic decalcification of the annulus is superior to traditional methods. We advocate the use of ultrasonic débridement as an adjunctive tool in calcified heart valve replacement.