Nikolaos A. Papakonstantinou

Sex differentiation with regard to coronary artery disease

Coronary artery disease was considered a male disease for many years. However, nowadays, coronary artery disease constitutes the leading cause of death in women, although there are a lot of gender-related differences regarding the presentation of acute myocardial infarction, its diagnosis, its treatment, short- and long-term mortality rates, and post-acute myocardial infarction complications. Generally, women have smaller and stiffer hearts and cardiac vessels, suffering a greater extent of atherosclerosis and endothelial and smooth muscle dysfunction. They are usually older than men and they have more comorbidities such as hypertension, renal impairment, and diabetes mellitus. Moreover, female coronary artery disease, the diagnosis of which is more complicated due to more false negative results of some diagnostic methods in women, is more often presented with atypical symptoms and womens symptoms of typical or atypical angina are more severe. Furthermore, women delay significantly more in seeking care and they are more frequently undertreated. Finally, women are associated with generally poorer in-hospital and long-term prognosis having almost two-fold higher early mortality and they are more prone to complications such as bleeding complications, shock, and heart failure, as well as to post-myocardial infarction depression and poorer physical function and mental health. In this review, we discuss these sex-related differences according to current literature.

The “benefits” of the mini-extracorporeal circulation in the minimal invasive cardiac surgery era

Mini-extracorporeal circulation (MECC) constitutes a novel miniaturized cardiopulmonary bypass (CPB) circuit, heparin-coated and primed with aprotinin. Its membrane oxygenation is similar to conventional cardio-pulmonary bypass (CCPB), but it is a completely closed-volume system due to the lack of the venous reservoir which has been removed. In a mini circuit, the reservoir is the patient himself. Consequently, air entering the venous cannula is avoided. Nevertheless, the capabilities of MECC have been expanded either by the inclusion of a suction device that is only activated on direct contact with liquid in some circuits or by postoperative autotransfusion of the wrecked erythrocytes by a separate suction device with a cell-saver. Although the tubing diameter is similar between the two systems, the tubing length of the MECC is around half that of the CCPB, resulting in the restriction of priming volume. As a consequence, a higher hematocrit thus a limited need for perioperative blood transfusion is achieved due to less hemodilution. In addition, the inflammatory response is also diminished as a result of less artificial surface area interacting with blood. Finally, a lower dose of heparin is required prior to MECC than prior to CCPB.

Radial artery as graft for coronary artery bypass surgery: Advantages and disadvantages for its usage focused on structural and biological characteristics

Radial artery (RA) is the most popular arterial graft after the left internal thoracic artery in both low- and high-risk patients undergoing coronary artery bypass grafting. Various arterial grafts such as the right internal thoracic artery, the right gastroepiploic artery, and the inferior epigastric artery have also gained ground over the past 30 years because of the intimal hyperplasia and atherosclerosis of the saphenous vein leading to late graft occlusion. In this review article we would like to present the utility of the RA as a graft, focused mainly on its structural and biological characteristics.

Mechanisms of oxidative stress and myocardial protection during open-heart surgery.

Cold heart protection via cardioplegia administration, limits the amount of oxygen demand. Systemic normothermia with warm cardioplegia was introduced due to the abundance of detrimental effects of hypothermia. A temperature of 32–33°C in combination with tepid blood cardioplegia of the same temperature appears to be protective enough for both; heart and brain. Reduction of nitric oxide (NO) concentration is in part responsible for myocardial injury after the cardioplegic cardiac arrest. Restoration of NO balance with exogenous NO supplementation has been shown useful to prevent inflammation and apoptosis. In this article, we discuss the “deleterious” effects of the oxidative stress of the extracorporeal circulation and the up-to-date theories of “ideal” myocardial protection.

Coronary endarterectomy: New flavors from old recipes

Coronary endarterectomy is an old surgical procedure against coronary artery disease first described by Baily et al. in 1957. Despite its first adverse results, several current publications have shown that coronary endarterectomy with on-pump or off-pump coronary artery bypass grafting can be safely performed with acceptable mortality, morbidity, and angiographic patency rates. Coronary endarterectomy can assure complete revascularization supplying the myocardium with satisfactory blood flow in cases of a diffusely diseased left anterior descending artery or diffuse calcification, thus preventing residual ischemia. Hence, it is important to evaluate current results, rethink this old recipe, and redefine its indications.

Cardiac surgery or interventional cardiology? Why not both? Let's go hybrid

A hybrid strategy, firstly performed in the 1990s, is a combination of tools available only in the catheterization laboratory with those available only in the operating room in order to minimize surgical morbidity and face with any cardiovascular lesion. The continuous evolution of stent technology along with the adoption of minimally invasive surgical approaches, make hybrid approaches an attractive alternative to standard surgical or transcatheter techniques for any given set of cardiovascular lesions. Examples include hybrid coronary revascularization, when an open surgical anastomosis of the left internal mammary artery to the left anterior descending coronary artery is performed along with stent implantation in non-left anterior descending coronary vessels, open heart valve surgery combined with percutaneous coronary interventions to coronary lesions, hybrid aortic arch debranching combined with endovascular grafting for thoracic aortic aneurysms, hybrid endocardial and epicardial atrial fibrillation procedures, and carotid artery stenting along with coronary artery bypass grafting. The cornerstone of success for all of these methods is the productive collaboration between cardiac surgeons and interventional cardiologists. The indications and patient selection of these procedures are still to be defined. However, high-risk patients have already been shown to benefit from hybrid approaches.

The role of myocardial ischaemic preconditioning during beating heart surgery: biological aspect and clinical outcome

Short periods of ischaemia consecutive to reperfusion periods before a sustained ischaemic condition, the so-called ischaemic preconditioning (IP), aim to protect myocardial cells against prolonged ischaemia. IP appears as a considerable endogenous cardioprotective mechanism decreasing the infarct size after total occlusion in either experimental models or humans. Angina periods before an acute coronary syndrome limit the myocardial infarction being protective for the myocardium. Our report aims to review the international bibliography of the IP during off-pump coronary artery bypass grafting.

Endovascular stent grafting for ascending aorta diseases

Objective Conventional open surgery encompassing cardiopulmonary bypass has been traditionally used for the treatment of ascending aorta diseases. However, more than one in five of these patients will be finally considered unfit for open repair. We conducted a systematic review and meta‐analysis to investigate the role of thoracic endovascular aortic repair (TEVAR) for aortic diseases limited to the ascending aorta. Methods The current meta‐analysis was conducted using the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines. We investigated patients’ baseline characteristics along with early (30 days/in‐hospital stay) and late (beyond 30 days/in‐hospital stay) outcomes after TEVAR limited to the ascending aorta and not involving the arch vessels. Separate analyses for case reports and case series were conducted, and pooled proportions with 95% confidence intervals (CIs) of outcome rates were calculated. Results Approximately 67% of the patients had a prior cardiac operation. TEVAR was performed mainly for acute or chronic Stanford type A dissection (49%) or pseudoaneurysm (28%). The device was usually delivered through the femoral artery (67%), and rapid ventricular pacing was used in nearly half of the patients. Technical success of the method was 95.5% (95% CI, 87.8‐99.8). Among the early outcomes, conversion to open repair was 0.7% (95% CI, 0.1‐4.8), whereas mortality was 2.9% (95% CI, 0.02‐8.6). We estimated a pooled rate of 1.8% (95% CI, 0.1‐7.0) for neurologic events (stroke or transient ischemic attack) and 0.8% (95% CI, 0.1‐5.6) for myocardial infarction. Late endoleak was recorded in 16.4% (95% CI, 8.2‐26.0), and 4.4% (95% CI, 0.1‐12.4) of the population died in the postoperative period. Finally, reoperation was recorded in 8.9% (95% CI, 3.1‐16.4) of the study sample. Conclusions TEVAR in the ascending aorta seems to be safe and feasible for selected patients with various aortic diseases, although larger studies are required.

Transaortic video-assisted excision of a left ventricular hemangioma

A 44-year-old asymptomatic female undergoing a transthoracic echocardiogram was found to have a 2.2-cm mass arising from the interventricular septum near the posterior papillary muscle (Figure 1a), which was also visualized on a cardiac magnetic resonance image (Figure 1b). A coronary angiogram showed normal coronary arteries and the presence of a “tumor blush” (Figure 1c). At the time of surgery, cardiopulmonary bypass was established with aortic and bicaval cannulation. The heart was arrested with antegrade, cold blood cardioplegia. A transverse aortotomy was performed and a 10-mm Karl Storz (Tuttlingen, Germany) rigid thoroscope was advanced through the aortic valve. The tumor was easily visualized at the apical portion of the interventricular septum. The mass was grasped with a Duvall forceps and totally excised from the mitral chordae and papillary muscle under direct thorascopic visualization (Figure 2a1-3). The tumor appeared reddish and polypoid (Figure 2b). The patient tolerated the procedure well and had an uncomplicated postoperative course. The histology was consistent with a cardiac capillary hemangioma. A postoperative echocardiogram showed no residual tumor.

Total arterial revascularization: A superior method of cardiac revascularization

For over 40 years, the left internal thoracic artery has been used as the gold standard for myocardial revascularization and anastomosis over the left anterior descending artery due to its excellent patency rates. However, the right internal thoracic artery behaves in the same manner as the left, also having excellent long-term patency. Hence, no patient should be deprived of the benefits of total arterial revascularization allowed by the bilateral use of both internal thoracic arteries.