Coronary CT angiography for the detection of coronary artery stenosis in patients referred for transcatheter aortic valve replacement

BACKGROUND

Coronary CT has become the foremost noninvasive imaging modality for detecting coronary stenoses in patients with suspected coronary artery disease. Nevertheless, little is known about its performance in patients undergoing transcatheter aortic valve replacement (TAVR).

OBJECTIVE

This study investigates the diagnostic performance of coronary CT angiography in patients referred for TAVR.

METHODS

One hundred and fifteen consecutive patients with severe aortic stenosis underwent CT angiography with retrospective electrocardiography triggered acquisition and an iterative reconstruction algorithm, of whom 23 (20%) had prior coronary artery bypass graft (CABG) surgery. Diagnostic accuracy of CT for detecting significant coronary stenosis (≥ 50% luminal diameter stenosis in segments ≥ 2 mm) in the left main, proximal, or middle segments of coronary arteries and bypass grafts was compared with that of invasive coronary angiography.

RESULTS

In the overall study population, the sensitivity, specificity, and positive and negative predictive value of CT angiography for the detection of coronary segment or bypass graft lesions were 96% (47 of 49), 73% (48 of 66), 72% (47 of 65), and 96% (48 of 50), respectively. The per-patient diagnostic yield of CT angiography was consistent among patients without prior CABG (93% [28 of 30], 73% [45 of 62], 62% [28 of 45], and 96% [45 of 47], respectively) and among patients with prior CABG (100% [19 of 19], 75% [3 of 4], 95% [19 of 20], and 100% [3 of 3], respectively).

CONCLUSION

Among patients referred for TAVR, coronary CT angiography with retrospective gating and iterative reconstruction may allow detection of significant stenosis in the proximal or middle segments of coronary arteries and could permit the evaluation of patients after bypass grafts.

Enriching hematopoietic, endothelial and mesenchymal functional progenitors by short-term culture of steady-state peripheral blood mononuclear cells obtained from healthy donors and ischemic patients

BACKGROUND

Non-mobilized peripheral blood contains mostly committed cells with limited numbers of early progenitors.

OBJECTIVES

To enrich functional progenitor cells from healthy donors and ischemic heart disease patients by short-term culture of mononuclear cells with defined culture conditions.

METHODS

Mononuclear cells obtained from healthy donors and ischemic heart disease patients were cultured for7 days in a cytokine cocktail. We tested the multilineage differentiation capacities and phenotype of cultured cells.

RESULTS

The short-term culture (7 days) of all study groups with a defined cytokine cocktail resulted in two distinct cell populations (adherent and non-adherent) that differed in their differentiation capacities as well as their cell surface markers. Cultured adherent cells showed higher differentiation potential and expressed endothelial and mesenchymal fibroblast-like surface markers as compared to fresh non-cultured mononuclear cells. The non-adherent cell fraction demonstrated high numbers of colony-forming units, indicating a higher differentiation potential of hematopoietic lineage.

CONCLUSIONS

This study proved the feasibility of increasing limited numbers of multipotent progenitor cells obtained from the non-mobilized peripheral blood of healthy donors and ischemic patients. Moreover, we found that each of the two enriched subpopulations (adherent and non-adherent) has a different differentiation potential (mesenchymal, endothelial and hematopoietic).

Higher Syntax score is not predictive of late mortality in "real-world" patients with multivessel coronary artery disease undergoing coronary artery bypass grafting

BACKGROUND

The Syntax score (SS) is a helpful tool for determining the optimal revascularization strategy regarding coronary artery bypass surgery (CABG) vs. percutaneous coronary intervention (PCI) in patients with complex coronary disease. While an association between higher SS and mortality was found for PCI patients, no such association was found for CABG patients.

OBJECTIVES

To assess whether the SS predicts late mortality in patients undergoing CABG in a real-world setting.

METHODS

The study included 406 consecutive patients referred for CABG over a 2 year period. Baseline and clinical characteristics were collected. Angiographic data SS were interpreted by an experienced angiographer. Patients were divided into three groups based on SS tertiles: low ≤ 21 (n = 205), intermediate 22-31 (n = 138), and high ≥ 32 (n = 63). Five year mortality was derived from the National Mortality Database.

RESULTS

Compared with low SS, patients with intermediate and high scores were significantly older (P = 0.02), had lower left ventricular ejection fraction (64% vs. 52% and 48%, P < 0.001) and greater incidence of acute coronary syndrome, left main disease, presence of chronic total occlusion of the left anterior descending and/or right coronary artery, and a higher EuroSCORE (5% vs. 5% and 8%, P < 0.01). Patients with intermediate and high SS had higher 5 year mortality rates (18.1% and 19%, respectively) compared to patients with low score (9.8%, P = 0.04). On multivariate analysis, SS was not an independent predictor of late mortality.

CONCLUSION

Patients with lower SS had lower mortality after CABG, which is attributable to lower baseline risk. SS is not independently predictive of late mortality in patients with multi-vessel coronary artery disease undergoing CABG.

Fluid-structure interaction model of aortic valve with porcine-specific collagen fiber alignment in the cusps

Native aortic valve cusps are composed of collagen fibers embedded in their layers. Each valve cusp has its own distinctive fiber alignment with varying orientations and sizes of its fiber bundles. However, prior mechanical behavior models have not been able to account for the valve-specific collagen fiber networks (CFN) or for their differences between the cusps. This study investigates the influence of this asymmetry on the hemodynamics by employing two fully coupled fluid-structure interaction (FSI) models, one with asymmetric-mapped CFN from measurements of porcine valve and the other with simplified-symmetric CFN. The FSI models are based on coupled structural and fluid dynamic solvers. The partitioned solver has nonconformal meshes and the flow is modeled by employing the Eulerian approach. The collagen in the CFNs, the surrounding elastin matrix, and the aortic sinus tissues have hyperelastic mechanical behavior. The coaptation is modeled with a master-slave contact algorithm. A full cardiac cycle is simulated by imposing the same physiological blood pressure at the upstream and downstream boundaries for both models. The mapped case showed highly asymmetric valve kinematics and hemodynamics even though there were only small differences between the opening areas and cardiac outputs of the two cases. The regions with a less dense fiber network are more prone to damage since they are subjected to higher principal stress in the tissues and a higher level of flow shear stress. This asymmetric flow leeward of the valve might damage not only the valve itself but also the ascending aorta.

Factors affecting survival in men versus women following transcatheter aortic valve implantation

Although transcatheter aortic valve implantation (TAVI) for severe aortic stenosis is becoming an established technique, the impact of gender-related differences remains unclear. Two hundred twenty-four consecutive patients undergoing TAVI were prospectively followed up in a tertiary medical center. The primary end point of the present study was all-cause mortality at 2 years of follow-up. Interaction-term analysis was used to identify gender-specific predictors of mortality after TAVI. Fifty-seven percent of the study patients were women. Age was similar (82 ± 7 years). Compared with men, women had a lower frequency of coronary artery disease (CAD) and a higher baseline left ventricular ejection fraction (LVEF). The cumulative probability of all-cause mortality was significantly lower among women (8.6%) compared with men (26.8%; log-rank p value <0.001). A lower baseline LVEF (<45%) was associated with a significant, more than fourfold (p = 0.0019 and 0.048, respectively), increase in mortality risk among both men and women (p value for gender-by-LVEF interaction = 0.87). In contrast, the risk associated with the presence of previous CAD was shown to be gender related. Thus, in women, CAD was associated with a pronounced >14-fold increase in mortality risk, whereas in men, CAD was not associated with a significant mortality risk (p value for gender-by-LVEF interaction = 0.01). In conclusion, our findings suggest that risk assessment before TAVI should consider gender-specific differences in survival and risk factors.

Tracheostomy after cardiac surgery: timing of tracheostomy as a risk factor for mortality

OBJECTIVES

The optimal timing for tracheostomy after cardiac surgery in patients undergoing prolonged ventilation is controversial. The aim of this study was to assess the effect of tracheostomy timing on short- and long-term mortality of these patients.

DESIGN

Retrospective study of prospectively collected data.

SETTING

Cardiac surgical intensive care unit (ICU) in a tertiary-care, university-affiliated hospital.

PARTICIPANTS

All patients undergoing tracheostomy after cardiac surgery between September 2004 and March 2013 were included.

INTERVENTIONS

The authors compared the outcome in 2 groups of patients according to the timing of tracheostomy: Group I, early-intermediate tracheostomy (0-14 days) and Group II, late tracheostomy (≥15 days).

MEASUREMENTS AND MAIN RESULTS

During the study period, 6,069 patients underwent cardiac surgery; among them, 199 patients (3.26%) received a tracheostomy. There were 90 patients in Group I and 109 patients in Group II. There was no significant difference in the severity of the patients' illness between the groups. The mortality rate at 3 months, 6 months, 1 year, and 2 years was 37%, 48%, 56%, and 58% in Group I, respectively, and 58%, 70%, 74%, and 77% in Group II, respectively (p< 0.01).

CONCLUSIONS

Early-intermediate (0-14 days) tracheostomy after cardiac surgery in patients requiring prolonged mechanical ventilation was associated with reduced mortality compared with late tracheostomy (≥15 days).

Adult respiratory distress syndrome following cardiac surgery

BACKGROUND

Severe lung injury with the development of acute respiratory distress syndrome (ARDS) is a serious complication of cardiac surgery. The aim of this study was to determine the incidence, risk factors, and mortality of ARDS following cardiac surgery.

METHODS

We retrospectively analyze data in the period between January 2005 and March 2013.

RESULTS

Of 6069 patients who underwent cardiac surgery during the study period, 37 patients developed ARDS during the postoperative period. The incidence of ARDS was 0.61%, with a mortality of 40.5% (15 patients). Multivariate regression analysis identified previous cardiac surgery, complex cardiac surgery, and more than three transfusions with packed red blood cells (PRBC) were independent predictors for developing ARDS.

CONCLUSIONS

ARDS remains a serious, but very rare complication associated with significant mortality. In our study, previous cardiac surgery, complex cardiac surgery, and more than three transfusions of PRBC were independent predictors for the development of ARDS.

The origin of human mesenchymal stromal cells dictates their reparative properties

Background

Human mesenchymal stromal cells (hMSCs) from adipose cardiac tissue have attracted considerable interest in regard to cell‐based therapies. We aimed to test the hypothesis that hMSCs from the heart and epicardial fat would be better cells for infarct repair.

Methods and Results

We isolated and grew hMSCs from patients with ischemic heart disease from 4 locations: epicardial fat, pericardial fat, subcutaneous fat, and the right atrium. Significantly, hMSCs from the right atrium and epicardial fat secreted the highest amounts of trophic and inflammatory cytokines, while hMSCs from pericardial and subcutaneous fat secreted the lowest. Relative expression of inflammation‐ and fibrosis‐related genes was considerably higher in hMSCs from the right atrium and epicardial fat than in subcutaneous fat hMSCs. To determine the functional effects of hMSCs, we allocated rats to hMSC transplantation 7 days after myocardial infarction. Atrial hMSCs induced greatest infarct vascularization as well as highest inflammation score 27 days after transplantation. Surprisingly, cardiac dysfunction was worst after transplantation of hMSCs from atrium and epicardial fat and minimal after transplantation of hMSCs from subcutaneous fat. These findings were confirmed by using hMSC transplantation in immunocompromised mice after myocardial infarction. Notably, there was a correlation between tumor necrosis factor‐α secretion from hMSCs and posttransplantation left ventricular remodeling and dysfunction.

Conclusions

Because of their proinflammatory properties, hMSCs from the right atrium and epicardial fat of cardiac patients could impair heart function after myocardial infarction. Our findings might be relevant to autologous mesenchymal stromal cell therapy and development and progression of ischemic heart disease.

Pre-operative systolic anterior motion of the mitral valve in a patient undergoing mitral valve repair

A patient with myxomatous mitral valve prolapse underwent mitral mitral valve repair due to severe symptomatic mitral regurgitation. Preoperative echocardiography demonstrated systolic anterior motion of the mitral valve. This finding disappeared once spontaneous chordal rupture occurred, resulting in a flail posterior mitral leaflet. As the patient was considered at high risk of developing post-repair SAM, he was operated on using surgical techniques aimed at lowering the risk of this complication. Despite this, post-repair SAM did develop and could only be eliminated by a surgical edge-to-edge (Alfieri) repair.

Trans-catheter aortic valve implantation for non-classical indications

BACKGROUND

Trans-catheter aortic valve implantation (TAVI) has emerged as a novel therapeutic approach for patients with severe tricuspid aortic stenosis (AS) not suitable for aortic valve replacement.

OBJECTIVES

To describe our initial single-center experience with TAVI in patients with "off-label" indications.

METHODS

Between August 2008 and December 2011 we performed TAVI in 186 patients using trans-femoral, transaxillary, trans-apical and trans-aortic approaches. In 11 patients (5.9%) TAVL was undertaken due to: a) pure severe aortic regurgitation (AR) (n = 2), b) prosthetic aortic valve (AV) failure (n = 5), c) bicuspid AV stenosis (n = 2), and d) prosthetic valve severe mitral regurgitation (MR) (n = 2).

RESULTS

Implantation was successful in all: six patients received a CoreValve and five patients an Edwards-Sapien valve. In-hospital mortality was 0%. Valve hemodynamics and function were excellent in all patients except for one who received an Edwards-Sapien that was inside a Mitroflow prosthetic AV and led to consistently high trans-aortic gradients. No significant residual regurgitation in AR and MR cases was observed.

CONCLUSIONS

TAVI is a good alternative to surgical AV replacement in high risk or inoperable patients with severe AS. TAVI for non-classical indications such as pure AR, bicuspid AV, and failed prosthetic aortic and mitral valves is feasible and safe and may be considered in selected patients.