Perioperative use of iloprost in cardiac surgery patients diagnosed with heparin-induced thrombocytopenia-reactive antibodies or with true HIT (HIT-reactive antibodies plus thrombocytopenia): An 11-year experience

Thrombocytopenia and thromboembolism(s) may develop in heparin immune-mediated thrombocytopenia (HIT) patients after reexposure to heparin. At the Onassis Cardiac Surgery Center, 530 out of 17,000 patients requiring heart surgery over an 11-year period underwent preoperative HIT assessment by ELISA and a three-point heparin-induced platelet aggregation assay (HIPAG). The screening identified 110 patients with HIT-reactive antibodies, out of which 46 were also thrombocytopenic (true HIT). Cardiac surgery was performed in HIT-positive patients under heparin anticoagulation and iloprost infusion. A control group of 118 HIT-negative patients received heparin but no iloprost during surgery. For the first 20 patients, the dose of iloprost diminishing the HIPAG test to ≤5% was determined prior to surgery by in vitro titration using the patients' own plasma and donor platelets. In parallel, the iloprost "target dose" was also established for each patient intraoperatively, but before heparin administration. Iloprost was infused initially at 3 ng/kg/mL and further adjusted intraoperatively, until ex vivo aggregation reached ≤5%. As a close correlation was observed between the "target dose" identified before surgery and that established intraoperatively, the remaining 90 patients were administered iloprost starting at the presurgery identified "target dose." This process significantly reduced the number of intraoperative HIPAG reassessments needed to determine the iloprost target dose, and reduced surgical time, while maintaining similar primary clinical outcomes to controls. Therefore, infusion of iloprost throughout surgery, under continuous titration, allows cardiac surgery to be undertaken safely using heparin, while avoiding life-threatening iloprost-induced hypotension in patients diagnosed with HIT-reactive antibodies or true HIT.

Left ventricular pseudoaneurysm formation: Two cases and review of the literature

Left ventricular wall rupture (LVWR) comprises a complication of acute myocardial infarction (AMI). Acute LVWR is a fatal condition, unless the formation of a pseudoaneurysm occurs. Several risk factors have been described, predisposing to LVWR. High index of suspicion and imaging techniques, namely echocardiography and computed tomography, are the cornerstones of timely diagnosis of the condition. As LVWR usually leads to death, emergency surgery is the treatment of choice, resulting in significant reduction in mortality and providing favorable short-term outcomes and adequate prognosis during late follow-up. Herein, we present two patients who were diagnosed with LVWR following AMI, and subsequent pseudoaneurysm formation. In parallel, we review the aforementioned condition.

Thyroid hormone signalling is altered in response to physical training in patients with end-stage heart failure and mechanical assist devices: potential physiological consequences?

OBJECTIVES

The present study investigated the potential of the failing myocardium of patients with ventricular assist devices (VAD) to respond to physiological growth stimuli, such as exercise, by activating growth signalling pathways. This may be of therapeutic relevance in identifying novel pharmacological targets for therapies that could facilitate recovery after VAD implantation.

METHODS

Twenty-two patients bridged to heart transplantation (HTx) with VAD were included in the study. A group of patients underwent moderate intensity aerobic exercise (GT), while another group of patients did not receive exercise training (CG). Thyroid hormone receptor alpha1 (TRα1) protein and total (t) and phosphorylated (p) protein kinase B (Akt) and c-Jun N-terminal kinase (JNK) kinase signalling were measured in myocardial tissue by western blotting at pre-VAD and pre-HTx period. In addition, Thyroid hormone (TH) levels were measured in plasma.

RESULTS

Peak oxygen consumption (VO2) at pre-HTx period was higher in patients subjected to training protocol [18.0 (0.8) for GT when compared with 13.7 (0.7) for CG group, P = 0.002]. N-terminal-prohormone of brain natriuretic peptide (NT-proBNP) levels were 1068 (148) for CG vs 626 (115) for GT group, P = 0.035. A switch towards up-regulation of physiological growth signalling was observed: the ratio of p-Akt/t-Akt was 2-fold higher in GT vs CG, P < 0.05 while p-JNK/t-JNK was 2.5-fold lower (P < 0.05) in GT vs CG, in pre-HTx samples. This response was accompanied by a 2.0-fold increase in TRα1 expression in pre-HTx samples with concomitant increase in circulating T3 in GT vs CG, P < 0.05. No differences in peak VO2, NT-proBNP, T3, TRα1, p/t-AKT and p/t-JNK were found between groups in the pre-VAD period.

CONCLUSIONS

The unloaded failing myocardium responded to physical training by enhancing thyroid hormone signalling. This response was associated with an up-regulation of Akt and suppression of JNK activation.

Right ventricular endocardial thermography in transplanted and coronary artery disease patients: first human application

BACKGROUND

We sought to evaluate for the first time in humans the safety and feasibility of right ventricular (RV) thermography in patients with coronary artery disease (CAD) and in patients after heart transplantation (Tx), in comparison to subjects without structural heart disease (controls).

METHODS

Ninety-one RV thermography procedures were performed in 16 patients with CAD, 19 hearttransplant recipients and 6 patients without structural heart disease. We recorded the temperature of the RV intracavitary blood and RV endocardial septum, and calculated their difference using a dedicated commercially available thermography catheter.

RESULTS

No complications were observed. CAD patients had a significantly higher temperature difference (0.19 +/- 0.11 degrees C) compared to both Tx patients (0.10 +/- 0.06 degrees C) and controls (0.07 +/- 0.04 degrees C) (p < 0.0001 and p = 0.003, respectively), whereas there was no significant difference between the Tx patients and controls (p = 0.65).

CONCLUSION

RV thermography in humans is feasible and safe. Patients with stable CAD present a significantly higher temperature difference in the RV endocardium compared to controls; clinically stable transplant recipients have temperatures similar to controls. This novel method corroborates previous findings supporting the inflammatory hypothesis of coronary atherosclerosis.

Increased number of circulating progenitor cells after implantation of ventricular assist devices

BACKGROUND

Bone marrow-derived circulating progenitor cells possess tissue repair potential, improving perfusion, left ventricular remodeling, and contractility in experimental models. We quantified and investigated the kinetics of 4 circulating progenitor cell sub-populations on the basis of CD34, CD133, and vascular endothelial growth factor receptor-2 (VEGFR-2) antigen expression.

METHODS

CD34+, CD34+/CD133+/VEGFR-2-, CD34+/CD133+/VEGFR-2+, and CD34+/CD133-/VEGFR-2+ cells were counted in 10 male patients with end-stage congestive heart failure. Five underwent left ventricular/biventricular assist device (LVAD/BiVAD) implantation (VAD group), and 5 were ineligible for VAD implantation (no-VAD group). Peripheral blood was collected at 3 time points for each patient: before, 15, and 60 days after VAD placement in the VAD group and at the same time points in the no-VAD group. Purified CD34+ cells were stained with anti-CD34, anti-CD133, and anti-VEGFR-2 monoclonal antibodies and analyzed by flow cytometry. Serum levels of granulocyte-colony stimulating factor (G-CSF), interleukin-8, vascular endothelial growth factor-alpha (VEGF-alpha), and B-type natriuretic peptide (BNP) were also measured.

RESULTS

In the VAD group the number of CD34+ cells/ml of blood tended to increase, from 159.6 +/- 137.0 at baseline to 428.9 +/- 224.3 at 15 days, and decreased to 343.8 +/- 165.7 at 60 days (p = 0.05 vs no-VAD group). In the other 3 cell populations, no significant differences occurred over time or between groups. A significant interaction between BNP levels and VAD status was observed (p = 0.005): BNP levels decreased over time in VAD patients vs no-VAD patients. G-CSF levels tended to decrease over time in both groups, but without a significant difference (p = 0.3). Serum levels of interleukin-8 and VEGF-alpha over time or between VAD and no-VAD patients were not significantly different.

CONCLUSIONS

After VAD implantation, a transient increase occurs in the number of circulating CD34+ cells, in parallel to a reduction in BNP levels. Release of these cells from the bone marrow may contribute to the improvement of tissue perfusion and cardiac recovery occasionally seen after VAD placement.

Orthotopic heart transplantation: ten years' clinical experience

INTRODUCTION

Heart transplantation is the "gold standard" in the treatment of patients with end-stage heart failure who satisfy strict selection criteria.

METHODS

We reviewed ten years' clinical experience (1996-2006) from 53 orthotopic transplants in our centre.

RESULTS

Low perioperative (3.7%) and long-term (7.5%) mortality rates yielded a 95% survival rate in the first year, 92% at five years, and 70% at ten years--significantly better than the corresponding rates worldwide. In addition, excellent functional recovery was achieved in all transplant recipients.

CONCLUSIONS

The strict application of international criteria in the selection of both candidates and donors, together with uninterrupted, multidisciplinary follow up, have made it feasible to perform heart transplantation with excellent results, despite the curiously low number of potential recipients and the shortage of acceptable donor hearts.

Inhaled iloprost controls pulmonary hypertension after cardiopulmonary bypass

PURPOSE

Severe pulmonary hypertension (PH) is a major cause of right ventricular (RV) dysfunction. Various iv vasodilator modalities have been used with limited results because of lack of pulmonary selectivity. The aim of the present controlled study was to evaluate the efficacy of inhaled iloprost, a synthetic prostacyclin analogue, in patients with elevated pulmonary vascular resistance (PVR) immediately after separation from cardiopulmonary bypass (CPB).

METHODS

Twelve patients with persistent PH after discontinuation of CPB were included in the study. In all patients standard hemodynamic monitoring was used. Inhaled iloprost was administered via nebulized aerosol at a cumulative dose of 0.2 micro g*kg(-1) for a total duration of 20 min. Complete sets of hemodynamic measurements were performed before inhalation (baseline), during and after cessation of the inhalation period. Echocardiographic monitoring of RV function was also used.

RESULTS

Inhaled iloprost induced a reduction in the transpulmonary gradient at the end of the inhalation period in comparison to baseline (9.33 +/- 3.83 mmHg vs 17.09 +/- 6.41 mmHg, P < 0.05). The mean pulmonary artery pressure to systemic artery pressure ratio decreased over this period (0.28 +/- 0.08 vs 0.45 +/- 0.17, P < 0.05). A statistically significant decrease of the PVR to systemic vascular resistance ratio was also observed (0.15 +/- 0.05 vs 0.21 +/- 0.05, P < 0.05). Improved indices of RV function were observed in echocardiographic monitoring.

CONCLUSION

Inhaled iloprost appears to be a selective pulmonary vasodilator and may be effective in the initial treatment of PH and the improvement of RV performance in the perioperative setting.