Current status of thoracic endografting and its adjunctive pharmacology

BACKGROUND

Thoracic endovascular aortic repair is a promising treatment modality. The advantages in the short term include shorter hospital stay, avoidance of lengthy invasive procedures, and decreased anesthesia time. It has made possible the treatment of elderly patients with coexisting comorbidities who otherwise would be difficult candidates for open surgery.

OBJECTIVE

Although the technical aspects of thoracic endovascular procedures have been described in the literature, the adjunct pharmacology has not been discussed. The aim of this study is therefore to review the clinical pharmacology necessary for procedural details in repair of patients with aortic aneurysms and aortic dissection.

METHODS

A literature search was performed using PUBMED by combining relevant Medical Subject Heading key words. The query was subsequently limited to English language, and involving "human". The articles were assessed for their validity, importance, and applicability. The publications were analyzed and clinically important data were collected and incorporated.

RESULTS/CONCLUSION

Thoracic endovascular aortic repair is a complex procedure on a morbid cohort of patients with aortic pathologies. The pharmacotherapy is a crucial component of the procedure: It is aimed at facilitating the endovascular procedure and improving outcomes.

Perioperative management of patients on adenosine diphosphate inhibitors in the era of drug-eluting stents: review of the literature and clinical implications

The current adenosine diphosphate inhibitors, ticlopidine and clopidogrel, are thienopyridine compounds that inhibit adenosine diphosphate mediated platelet aggregation. They interfere with platelet activation by selectively and irreversibly blocking P2Y12 sub-unit of the adenosine diphosphate receptor on the surface of platelets. This provides an antiplatelet effect that is additive to the inhibition of the thromboxane A2 pathway by aspirin. Dual antiplatelet therapy is extensively used in cardiovascular medicine. Randomized controlled trials have substantiated the fact that thrombotic complications after percutaneous coronary intervention procedures can be decreased by using dual antiplatelet therapy. However, there is a concern of bleeding due to enhanced and irreversible platelet inhibition in patients who will require any operation including coronary artery bypass grafting while on adenosine diphosphate inhibitors. This applies to a large population of patients requiring either coronary artery bypass grafting after angiographic definition of their coronary anatomy, or patients requiring semi-elective or urgent operation while under dual antiplatelet therapy. This concern is more present in era of drug-eluting stents, where long-term use of dual antiplatelet therapy is encouraged, and the incidence of late thrombosis after late cessation of adenosine diphosphate inhibitors is increasingly surfacing in the literature. The goal this review is to provide the medical chemistry of most commonly used adenosine diphosphate inhibitors, examine the literature on the effect of adenosine diphosphate inhibitors in hemorrhagic-related complications after surgical intervention, and provide the ramifications and alternatives in modern clinical practice.

A synopsis of research in cardiac apoptosis and its application to congestive heart failure

Cardiac apoptosis diminishes the contractile mass, which leads to heart failure. Apoptosis of cardiac non-myocytes also contributes to maladaptive remodeling and the transition to decompensated congestive heart failure. New antiapoptotic interventions and medications will be available within the next decade. The aim of this study is to provide a critical synopsis of research projects on cardiocyte apoptosis that have implications for current and future practice and to identify methods to prevent or attenuate apoptosis in patients who have poor ventricular function. A retrospective literature review reveals a great many important publications. However, very few investigators discuss the clinical ramifications of cardiocyte apoptosis, nor do they address the clinician who sees poor ventricular contractility daily. Most studies are still investigational and involve antiapoptotic agents such as broad-spectrum caspase inhibitors, antioxidants, calcium channel blockers, insulin-like growth-factor 1, and poly(adenosine diphosphate ribose) synthetase inhibitors. some options have already been incorporated into the clinical practices of cardiologists and cardiac surgeons: repairing or replacing diseased or damaged valves before ventricular function deteriorates; reducing afterload with medication or intra-aortic balloon pulsation in patients who display acute increases in afterload; decreasing catecholamine-induced cardiotoxicity in hemodynamically compromised patients, by using beta-blockers and phosphodiesterase inhibitors; and inserting intra-aortic balloon pumps or ventricular assist devices early in cases of failing myocardium. Coronary revascularization early in myocardial infarction is effective antiapoptotic therapy. Other therapeutic targets are cardiopulmonary bypass and aortic cross-clamping, both of which require reductions in associated myocardial apoptosis.

Antibody response to Cryptococcus neoformans capsular polysaccharide glucuronoxylomannan in patients after solid-organ transplantation

Cryptococcosis is an important complication of solid-organ transplantation, but the risk factors for disease are poorly understood. The goal of this study was to investigate whether specific or nonspecific serum immunoglobulin levels determined in samples obtained before and after solid-organ transplantation differed in patients who did or did not develop cryptococcosis after transplantation. We analyzed pretransplantation sera from 25 subjects, 15 who subsequently developed cryptococcosis and 10 who did not, and posttransplantation sera from 24 subjects, 13 who developed cryptococcosis and 11 who did not. All subjects received a tacrolimus-based immunosuppressive regimen. Total immunoglobulin levels were measured by immunodiffusion, and Cryptococcus neoformans capsular polysaccharide glucuronoxylomannan (GXM)-specific serum antibody levels were determined by enzyme-linked immunosorbent assays. The results showed that solid-organ transplantation had a significant effect on total immunoglobulin and GXM-reactive antibody levels. GXM-reactive antibody levels differed in subjects who did and did not develop cryptococcosis. In pretransplant serum samples, the levels of GXM-reactive immunoglobulin M (IgM) were significantly lower in subjects who developed cryptococcosis after transplantation than in those who did not. For posttransplant serum samples, the levels of GXM-reactive IgM and IgG were significantly higher among the subjects who developed cryptococcosis than among those who did not. These findings suggest that perturbations in the preexisting antibody or B-cell repertoire and/or related to treatment of rejection, transplantation, or immunosuppressive therapy could translate into an increased risk for transplant-associated cryptococcosis.

Apoptosis: pathophysiology and therapeutic implications for the cardiac surgeon

Cardiomyocyte apoptosis has been associated with the pathogenesis of heart failure as well as ischemic and inflammatory myocardial conditions. The aim of this study is to give a critical synopsis of cardiomyocyte apoptosis and identify methods to prevent or attenuate apoptosis in patients undergoing cardiac surgery. Clinical conditions and agents associated with decreased apoptotic index are early repair or replacement of valvular pathology before deterioration of ventricular function, afterload reduction with medication or intraaortic balloon pulsation in patients with acute increase in afterload or in hemodynamically compromised patients, decreasing catecholamine-induced cardiotoxicity by using beta-blockers, phosphodiesterase inhibitors, or early insertion of intraaortic balloon pulsation or ventricular assist device. Prompt coronary revascularization, which reduces myocardial ischemia time, is the most effective antiapoptotic therapy. Reduction of myocardial apoptosis associated with cardiopulmonary bypass and aortic cross-clamping are other therapeutic targets. Some investigational therapies include ischemic preconditioning and use of antiapoptotic medication such as the caspase inhibitors, antioxidants, calcium-channel blockers, the insulin-like growth factor-1, and the poly-adenosine diphosphate-ribose-synthetase inhibitors. Most of the therapeutic implications in reducing cardiomyocyte apoptosis are still in the experimental phase. Some options are already incorporated in the clinical practice of the cardiovascular surgeon. New therapeutic considerations include avoiding sustained and long-term use of catecholamines and reducing or avoiding cardiopulmonary bypass-when clinically feasible. Noncatecholamine inotropes should be preferred for patients undergoing heart failure surgery and for patients with low output syndrome after open-heart surgery. The lessons learned from apoptosis research reinforce more liberal and early insertion of intraaortic balloon pulsation or ventricular assist device in clinical low output states.

Cisplatin-induced renal toxicity: possible reversal by N-acetylcysteine treatment

Cisplatin administration is frequently associated with renal insufficiency and tubular dysfunction. In this article, a case of massive cisplatin overdose as a result of an accidental substitution for carboplatin is reported. The patient developed oliguric renal failure, hepatotoxicity, ototoxicity, peripheral neuropathy, blindness, and severe myelosuppression. A therapeutic trial with N-acetylcysteine to reverse renal toxicity was attempted. This article reviews the literature on cisplatin nephrotoxicity, with an emphasis on possible mechanisms involved, and suggests therapy for its modification.