Emaddin Kidher

Effect of Skeletonization of the Internal Thoracic Artery for Coronary Revascularization on the Incidence of Sternal Wound Infection

Use of the internal thoracic artery in coronary revascularization confers excellent benefit. We assessed the impact of skeletonization on the incidence of postoperative sternal wound infection in patients undergoing coronary artery bypass grafting. We also investigated whether there is an advantage in using this technique when harvesting both internal thoracic arteries in high-risk groups, such as diabetic patients. Skeletonization was associated with beneficial reduction in the odds ratio of sternal wound infection (odds ratio, 0.41; 95% confidence interval, 0.26 to 0.64). This effect was more evident when analyzing diabetic patients undergoing bilateral internal thoracic artery grafting (odds ratio, 0.19; 95% confidence interval, 0.10 to 0.34).

Aortic valve replacement for aortic stenosis in patients with concomitant mitral regurgitation: should the mitral valve be dealt with?

Co-existent mitral regurgitation may adversely influence both morbidity and mortality in patients undergoing aortic valve replacement for severe aortic stenosis. Whilst it is accepted that concomitant mitral intervention is required in severe, symptomatic mitral regurgitation, in cases of mild-moderate non-structural mitral regurgitation, improvement may be seen following aortic valve replacement alone, avoiding the increased risk of double-valve surgery. The exact benefit of such a conservative approach is, however, yet to be adequately quantified. We performed a systematic literature review identifying 17 studies incorporating 3053 patients undergoing aortic valve replacement for aortic stenosis with co-existing mitral regurgitation. These were meta-analysed using random effects modelling. Heterogeneity and subgroup analysis were assessed. Primary end points were change in mitral regurgitation severity and 30-day, 3-, 5- and 10-year mortality. Secondary end points were end-organ dysfunction (neurovascular, renal and respiratory), and the extent of ventricular remodelling following aortic valve replacement. Our results revealed improvement in the severity of mitral regurgitation following aortic valve replacement in 55.5% of patients, whereas 37.7% remained unchanged, and 6.8% worsened. No significant difference was seen between overall data and either the functional or moderate subgroups. The overall 30-day mortality following aortic valve replacement was 5%. This was significantly higher in moderate-severe mitral regurgitation than nil-mild mitral regurgitation both overall (p=0.002) and in the functional subgroup (p=0.004). Improved long-term survival was seen at 3, 5 and 10 years in nil-mild mitral regurgitation when compared with moderate-severe mitral regurgitation in all groups (overall p<0.0001, p<0.00001 and p=0.02, respectively). The relative risk of respiratory, renal and neurovascular complications were 7%, 6% and 4%, respectively. Reverse remodelling was demonstrated by a significant reduction in left-ventricular end-diastolic diameter and left-ventricular mass (p=0.0007 and 0.01, respectively), without significant heterogeneity. No significant change was seen in left-ventricular end-systolic diameter (p=0.10), septal thickness (p=0.17) or left atrial area (p=0.23). We conclude that despite reverse remodelling, concomitant moderate-severe mitral regurgitation adversely affects both early and late mortality following aortic valve replacement. Concomitant mitral intervention should therefore be considered in the presence of moderate mitral regurgitation, independent of the aetiology.

How to manage the left subclavian artery during endovascular stenting for thoracic aortic dissection? An assessment of the evidence.

BACKGROUND Despite the publication of recent guidelines for management of the left subclavian artery (LSA) during endovascular stenting procedures of the thoracic aorta, specific management for those presenting with dissection remains unclear. This systematic review attempts to address this issue. METHODS Systematic assessment of the published data on thoracic aorta dissection was performed identifying 46 studies, which incorporated 1,275 patients. Primary outcomes included the prevalence of left arm ischemia, stroke, spinal cord ischemia, endoleak, stent migration, and mortality. Outcomes were compared between patients with and without LSA coverage and revascularization incorporating factors such as the number of stents used, length of aorta covered, urgency of intervention, and type of dissection (acute or chronic). Statistical pooling techniques, χ(2) tests, and Fishers exact testing were used for group comparisons. RESULTS As compared with other outcomes, LSA coverage without revascularization in the presence of aortic dissection is much more likely to be complicated by left arm ischemia (prevalence increased from 0.0% to 4.0% [p = 0.021]), stroke (prevalence increased from 1.4% to 9.0% [p = 0.009]), and endoleak (prevalence increased from 4.0% to 29.3% [p = 0.001]). However, revascularization was not shown to reverse these effects. Longer aortic coverage (≥ 150 mm) was associated with an increased prevalence of spinal cord ischemia (from 1.3% to 12.5% [p = 0.011]) and mortality (from 1.3% to 15.6% [p = 0.003]). CONCLUSION In patients undergoing endovascular stenting for thoracic aortic dissection, in cases where LSA coverage is necessary, revascularization should be considered before the procedure to avoid complications such as left arm ischemia, stroke, and endoleak, and where feasible, an appropriate preoperative assessment should be carried out.

Quality of life after intervention on the thoracic aorta

Surgery on the thoracic aorta is challenging and historically associated with significant mortality and morbidity. In recent times, there has been increased emphasis on the importance of health-related quality of life (HRQOL) measures. It is seen as a development beyond isolated markers of outcome such as operative mortality and is particularly applicable to aortic surgery given the number of asymptomatic patients operated on (for prognostic grounds), and rapidly advancing endovascular technologies which require proper assessment. This systematic review provides an outline of all available literature detailing HRQOL in patients receiving intervention (both open and endovascular) on the thoracic aorta. In total, 30 studies were identified encompassing 4746 patients undergoing a variety of procedures from aortic root replacement to thoracoabdominal aortic aneurysm repair. While there were deficiencies in the underlying literature such as lack of baseline HRQOL assessment, the majority of the studies confirm that HRQOL after major aortic surgery (including on the elderly and in emergency situations) is acceptable and compares well to matched general populations. Strategies for improving the HRQOL in aortic surgery are summarized and include the need for surgeons to plan cerebral protection methods more carefully and to develop operative strategies to avoid reoperation or reintervention, as this is associated with deterioration of long-term HRQOL. Randomized studies measuring baseline and follow-up HRQOL at specific set points are needed. Innovative research methods could be employed in future studies with the aim of correlating HRQOL with imaging or physiological/inflammation biomarkers, or other end points such as aortic stiffness or wall shear stress to characterize disease progression and prognosis.

High aortic pulse wave velocity is associated with poor quality of life in surgical aortic valve stenosis patients

OBJECTIVES Aortic stiffness is an emerging risk factor for cardiovascular disease. The predictive value of aortic pulse wave velocity (PWV) for quality of life (QoL) and severity of surgical aortic valve stenosis (AS) have not been examined. METHODS PWV was measured in patients undergoing aortic valve replacement (AVR) for AS. QoL [SF-36 and European QoL 5-dimensions (EQ-5D) questionnaires] was assessed pre- and postoperatively (409 ± 159 days). PWV was analysed: (i) as a continuous variable and (ii) as a dichotomous variable (PWV-norm and PWV-high groups) according to the published normal reference value. RESULTS Fifty-six patients (16 females), mean age of 71 ± 8.4 years, were included, and 50 (89%) patients completed follow-up. The two groups were matched for age, gender and classical haemodynamic measurements. There was no significant relation between AS severity and PWV. PWV-norm patients (n = 35) scored significantly better than PWV-high (n = 21) patients in the EQ-5D visual analogue scale and the EQ-5D index pre- (P < 0.001 and P = 0.03, respectively) and postoperatively (P < 0.001 for both). In SF-36, PWV-norm group scored better than PWV-high group in physical health domains preoperatively and in all domains postoperatively. Spearmans correlation was significant between PWV and QoL component summaries pre- and postoperatively. Among PWV, age and gender, multiple regression analysis demonstrated PWV to be independently related to QoL pre- and postoperatively (P-values ranged from <0.01 to <0.05). CONCLUSIONS PWV does not correlate with AS severity, but is associated with QoL before and after AVR. The published European PWV reference values can be used to categorise preoperative AS patients for QoL risk stratification.

Do bigger hospitals or busier surgeons do better adult aortic or mitral valve operations

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether there is a relationship between hospital or surgeon volume (SV) and postoperative outcome in adult aortic or mitral valve surgery. One hundred and sixty papers were found using the specified search strategy, of which seven papers represented the best evidence to answer this question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, methodology scores, study weaknesses and results are tabulated. Outcomes assessed by these studies were variable; four papers used mortality, one paper used morbidity, one paper used care processes and one paper examined all the above-mentioned outcomes. Six papers investigated the effect of hospital volume (HV) on outcome whilst only one paper assessed the effect of both HV and SV on outcome. The type of valve operated on was also mixed; two papers studied aortic valve only, one paper studied mitral valve only and four papers studied both valves. The methodological quality and validity of each study was assessed by a predefined scoring system. The median total quality score was modest and not strong enough to support the conclusions reported by these studies. In addition, volume-outcome relationship can be affected by several factors related to patient, surgeon and hospital. These factors have not been considered in depth by the mentioned papers. However, there may be a positive relationship between hospital procedural volume and mortality which is more likely to be mediated by SV, and there is also a potential relationship with the rate of mitral valve repair and the use of bio-prosthetic valves in elderly patients. We conclude that regionalisation of adult aortic or mitral valve surgery based on such a limited number of modest quality studies would be an indefensible policy. The implementation of such a scheme can have many clinical, practical, economical and political consequences which have not been examined prospectively until today. Furthermore, the relationship between volume and other outcomes rather than mortality needs further assessment.

Human Induced Pluripotent Stem Cell-Derived Cardiomyocyte Encapsulating Bioactive Hydrogels Improve Rat Heart Function Post Myocardial Infarction

Summary Tissue engineering offers an exciting possibility for cardiac repair post myocardial infarction. We assessed the effects of combined polyethylene glycol hydrogel (PEG), human induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM), and erythropoietin (EPO) therapy in a rat model of myocardial infarction. PEG with/out iPSC-CMs and EPO; iPSC-CMs in saline; or saline alone was injected into infarcted hearts shortly after infarction. Injection of almost any combination of the therapeutics limited acute elevations in chamber volumes. After 10 weeks, attenuation of ventricular remodeling was identified in all groups that received PEG injections, while ejection fractions were significantly increased in the gel-EPO, cell, and gel-cell-EPO groups. In all treatment groups, infarct thickness was increased and regions of muscle were identified within the scar. However, no grafted cells were detected. Hence, iPSC-CM-encapsulating bioactive hydrogel therapy can improve cardiac function post myocardial infarction and increase infarct thickness and muscle content despite a lack of sustained donor-cell engraftment.

Assessment of Hemodynamic Conditions in the Aorta Following Root Replacement with Composite Valve-Conduit Graft.

This paper presents the analysis of detailed hemodynamics in the aortas of four patients following replacement with a composite bio-prosthetic valve-conduit. Magnetic resonance image-based computational models were set up for each patient with boundary conditions comprising subject-specific three-dimensional inflow velocity profiles at the aortic root and central pressure waveform at the model outlet. Two normal subjects were also included for comparison. The purpose of the study was to investigate the effects of the valve-conduit on flow in the proximal and distal aorta. The results suggested that following the composite valve-conduit implantation, the vortical flow structure and hemodynamic parameters in the aorta were altered, with slightly reduced helical flow index, elevated wall shear stress and higher non-uniformity in wall shear compared to normal aortas. Inter-individual analysis revealed different hemodynamic conditions among the patients depending on the conduit configuration in the ascending aorta, which is a key factor in determining post-operative aortic flow. Introducing a natural curvature in the conduit to create a smooth transition between the conduit and native aorta may help prevent the occurrence of retrograde and recirculating flow in the aortic arch, which is particularly important when a large portion or the entire ascending aorta needs to be replaced.

Aortic stiffness is an indicator of cognitive dysfunction before and after aortic valve replacement for aortic stenosis

OBJECTIVES Post-cardiac surgical cognitive dysfunction occurs more commonly following valvular procedures. Cognitive function has been related to vascular health status; however, the relation between pre-existent arterial stiffness and perioperative cognitive dysfunction is yet to be defined. The objective of this study was to assess whether aortic stiffness is related to cognitive dysfunction in surgical aortic stenosis (AS) pre- and postoperatively. METHODS Between June 2010 and August 2012, patients undergoing aortic valve replacement (AVR) for AS were recruited for inclusion in this prospective observational study. Aortic pulse wave velocity (PWV) was used as a measure of aortic stiffness and cognitive function was assessed using the computerized Cambridge Neuropsychological Test Automated Battery (CANTAB) preoperatively and (409 ± 159 days) post-AVR. RESULTS Fifty-six patients (age 71 ± 8.4 years) were recruited. Of the total, 50 (89%) completed postoperative follow-up. Pre- and postoperatively, patients with normal PWV (PWV-norm) had significantly superior delayed memory, sustained visual attention and executive function compared with those with high PWV (PWV-high). Immediate memory and decision-making were similar between groups. Postoperatively, improvement in cognitive function was more marked in PWV-high compared with PWV-norm patients. In two models of multiple regression analysis, PWV as a continuous variable was independently related to all preoperative main cognitive components as well as postoperative executive function. PWV as a dichotomous variable was independently related to all pre- and postoperative main cognitive function components. CONCLUSIONS AVR may not be associated with an independent or homogeneous effect on cognitive decline. Aortic PWV might be useful as an additional indicator for cognitive dysfunction before and after surgical intervention for AS.

An interesting collection of paraneoplastic syndromes in a patient with a malignant thymoma

Paraneoplastic neurological syndromes are conditions that manifest as the remote effects of cancer. These are very rare, occurring in 1/10000 patients with a malignancy, and include Lambert–Eaton myasthenic syndrome, limbic encephalitis, subacute cerebellar ataxia, opsoclonus-myoclonus, Stiff–Person Syndrome, retinopathies, chronic gastrointestinal pseudo-obstruction and sensory neuropathy. This report describes a case of 41-year-old man who presented with elements of multiple paraneoplastic syndromes, including chronic gastrointestinal pseudo-obstruction, myasthenia gravis-Lambert–Eaton overlap syndrome and polymyositis, and who was subsequently found to have a malignant thymoma. There are only three reported cases in the literature describing cases of Lambert–Eaton myasthenic syndrome in association with a thymoma, and only one case of a myasthenia gravis-Lambert–Eaton overlap syndrome in a patient with thymoma. However, there are no documented cases in the literature of this constellation of syndromes in a patient with a malignant thymoma.