Aiman Alken's scientific contributions

Publications (12)

Publications citing this author (73)

    • Khan and collaborators found that in most octogenarians hospital morbidity is increased, and hospital stay is longer [28]. On the contrary, Deschka et al. found that advanced age is correlated with a higher mortality, but not with prolonged ICU treatment or higher costs after cardiac surgery [29]. On the opposite, in a recent study by Meziere et al., age was found to be an independent risk factor of postoperative mortality and postoperative complications including cognitive dysfunction , with no impact of the choice of anesthetic technique on risk [30].
    [Show abstract] [Hide abstract] ABSTRACT: The elderly undergo cardiac surgery more and more frequently, often present multiple comorbidities, assume chronic therapies, and present a unique physiology. Aim of our study was to analyze the experience of a referral cardiac surgery center with all types of cardiac surgery interventions performed in patients ≥80 years old over a six years' period. A retrospective observational study performed in a university hospital. 260 patients were included in the study (3.5% of the patients undergoing cardiac surgery in the study period). Mean age was 82 ± 1.8 years. Eighty-five percent of patients underwent elective surgery, 15% unplanned surgery and 4.2% redo surgery. Intervention for aortic valve pathology and coronary artery bypass grafting were performed in 51% and 46% of the patients, respectively. Interventions involving the mitral valve were the 26% of the total, those on the tricuspid valve were 13% and those on the ascending aortic arch the 9.6%. Postoperative low output syndrome was identified in 44 patients (17%). Mortality was 3.9% and most of the patients (91%) were discharged from hospital in good clinical conditions. Hospital mortality was lower in planned vs unplanned surgery: 3.8% vs 14% respectively. Chronic obstructive pulmonary disease (OR 9.106, CI 2.275 - 36.450) was the unique independent predictor of mortality. Clinicians should be aware that cardiac surgery can be safely performed at all ages, that risk stratification is mandatory and that hemodynamic treatment to avoid complications is expected.
    Full-text · Article · Jan 2015
    • (2013) [26] 72. Abbreviation: QOL, quality of life; SF-12, Short-Form 12; SF-36, Short-Form 36; EQ- 5D, EuroQol-5D; HADS, Hospital Anxiety and Depression Scale
    Full-text · Article · Jun 2016 · Journal of Biomechanics
    • Compared with standard full sternotomy, PUS reduces postoperative ventilation time, ICU stay, bleeding complications, transfusion requirements, risk of mediastinitis, hospital length of stay, pain and costs. Furthermore, PUS offers a rapid postoperative recovery and cosmetic advantages[24,25]. Byrne et al.[4]reported excellent outcomes of a minimally invasive approach for treatment of aortic root and complex ascending pathologies.
    [Show abstract] [Hide abstract] ABSTRACT: Objectives: Classically, repair of extensive thoracic aortic pathologies including the aortic arch and descending aorta required two separate major surgical procedures via full sternotomy and a subsequent left lateral thoracotomy. We describe herein our preliminary institutional experience with minimally invasive single-stage extended thoracic aortic replacement employing the frozen elephant trunk (FET) technique via partial upper sternotomy (PUS) in 14 patients. Methods: Between December 2013 and January 2015, 14 consecutive patients with elective indications for FET underwent minimally invasive FET via PUS (PUS-FET) during moderate systemic hypothermia (28°C) and selective antegrade cerebral perfusion (ACP) using the E-vita Open® hybrid prosthesis (Jotec GmbH, Hechingen, Germany). The patients' mean age was 66 ± 6 years, and 9 patients (64%) were male. The arch vessels were reimplanted en bloc in all patients. Clinical data were prospectively entered into our institutional database. Results: The surgical procedure was successful in all patients with no need for conversion to full sternotomy. An additional David procedure was performed in 1 patient, whereas 2 patients received a concomitant Bentall procedure. There was no perioperative death or 30-day mortality. The mean cardiopulmonary bypass time was 214 ± 35 min, and the myocardial ischaemic time was 125 ± 14 min. The ACP time was 54 ± 9 min, whereas the ventilation time reached 11 ± 4 h. Intensive care unit stay was 2 ± 3 days. Chest tube drainage within the first 24 h was 460 ± 130 ml. None of the 14 patients required re-exploration for bleeding. Patients were discharged after a hospital length of stay of 9 ± 2 days. No postoperative permanent neurological complication occurred. Two patients (14%) experienced temporary delirium with complete resolution of symptoms prior to discharge from the hospital. Conclusions: Our preliminary experience suggests that minimally invasive single-stage extended thoracic aortic replacement can safely and reproducibly be performed by employing the concept of PUS-FET.
    Full-text · Article · Jan 2016
    • A significant effect of valve hemodynamics on platelet activation for two differing valve designs (bileaflet. vs. monoleaflet) was also observed in patients (Laas et al., 2003). The AbioCor TAH study indicated that while no evidence of significant hemolysis was observed in animal or human patients studies (Dowling et al., 2004; Samuels et al., 2005), the majority of patients died of stroke related complications.
    [Show abstract] [Hide abstract] ABSTRACT: Thrombotic complications with mechanical circulatory support (MCS) devices remain a critical limitation to their long-term use. Device-induced shear forces may enhance the thrombotic potential of MCS devices through chronic activation of platelets, with a known dose-time response of the platelets to the accumulated stress experienced while flowing through the device-mandating complex, lifelong anticoagulation therapy. To enhance the thromboresistance of these devices for facilitating their long-term use, a universal predictive methodology entitled device thrombogenicity emulation (DTE) was developed. DTE is aimed at optimizing the thromboresistance of any MCS device. It is designed to test device-mediated thrombogenicity, coupled with virtual design modifications, in an iterative approach. This disruptive technology combines in silico numerical simulations with in vitro measurements, by correlating device hemodynamics with platelet activity coagulation markers-before and after iterative design modifications aimed at achieving optimized thrombogenic performance. The design changes are first tested in the numerical domain, and the resultant device conditions are then emulated in a hemodynamic shearing device (HSD) in which platelet activity is measured under device emulated conditions. As such, DTE can be easily incorporated during the device research and development phase-achieving minimization of the device thrombogenicity before prototypes are built and tested thereby reducing the ultimate cost of preclinical and clinical trials. The robust capability of this predictive technology is demonstrated here in various MCS devices. The presented examples indicate the potential of DTE for reducing device thrombogenicity to a level that may obviate or significantly reduce the extent of anticoagulation currently mandated for patients implanted with MCS devices for safe long-term clinical use.
    Full-text · Article · Dec 2012
    • In addition to haemodilution, many other factors during CPB could disturb the microcirculatory perfusion. Blood contact with the ECC tubing activates the coagulation cascade [11, 12]. Fibrin and fibrinogen are deposited onto the exposed surfaces and cause thrombin adherence and activation.
    [Show abstract] [Hide abstract] ABSTRACT: OBJECTIVES To reduce the complications associated with cardiopulmonary bypass (CPB) during cardiac surgery, many modifications have been made to conventional extracorporeal circulation systems. This trend has led to the development of miniaturized extracorporeal circulation systems. Cardiac surgery using conventional extracorporeal circulation systems has been associated with significantly reduced microcirculatory perfusion, but it remains unknown whether this could be prevented by an mECC system. Here, we aimed to test the hypothesis that microcirculatory perfusion decreases with the use of a conventional extracorporeal circulation system and would be preserved with the use of an miniaturized extracorporeal circulation system.
    Full-text · Article · Jun 2012