The Radial Artery for Coronary Bypass Grafting: The Fifth Decade

BACKGROUND

In 1989, we reported the use of the radial artery as a second target conduit for coronary artery bypass grafting. However, underpowered randomized trials have reported differences in clinical outcomes between the radial artery and other grafts. As we approach 50 years of experience with radial artery grafting, we reviewed the literature to determine the second-best target vessel for coronary operations.

METHODS

An electronic review of the literature with an emphasis on randomized controlled trials, propensity-matched observational series, and meta-analyses identified a large population of patients who received arterial conduit and saphenous vein grafts.

RESULTS

The radial artery has been proven to be reliable as a second target conduit for coronary artery bypass grafting, with outcomes and patency rates superior to those for saphenous vein graft. It has also been proven to be both safe and effective as a third conduit in the territory of the right coronary artery. A paucity of evidence with few comparable series limits the use of the gastroepiploic artery.

CONCLUSION

In its fifth decade of use, we can definitively conclude that the aorto-to-coronary radial bypass graft is the conduit of choice for coronary operations after the left internal thoracic artery to the left anterior descending artery.

Changes of the coronary arteries and cardiac microvasculature with aging: Implications for translational research and clinical practice

Aging results in functional and structural changes in the cardiovascular system, translating into a progressive increase of mechanical vessel stiffness, due to a combination of changes in micro-RNA expression patterns, autophagy, arterial calcification, smooth muscle cell migration and proliferation. The two pivotal mechanisms of aging-related endothelial dysfunction are oxidative stress and inflammation, even in the absence of clinical disease. A comprehensive understanding of the aging process is emerging as a primary concern in literature, as vascular aging has recently become a target for prevention and treatment of cardiovascular disease. Change of life-style, diet, antioxidant regimens, anti-inflammatory treatments, senolytic drugs counteract the pro-aging pathways or target senescent cells modulating their detrimental effects. Such therapies aim to reduce the ineluctable burden of age and contrast aging-associated cardiovascular dysfunction. This narrative review intends to summarize the macrovascular and microvascular changes related with aging, as a better understanding of the pathways leading to arterial aging may contribute to design new mechanism-based therapeutic approaches to attenuate the features of vascular senescence and its clinical impact on the cardiovascular system.

Sternal wound closure in the current era: the need of a tailored approach

OBJECTIVE

Median sternotomy remains the most common access to perform cardiac surgery procedures. However, the experience of the operating surgeon remains a crucial factor during sternal closure to avoid potential complications related to poor sternal healing, such as mediastinitis. Considering the lack of major randomized controlled trials and the heterogeneity of the current literature, this narrative review aims to summarize the different techniques and approaches to sternal closure with the aim to investigate their reflections into clinical outcomes and to inform the choice on the most effective closure method after median sternotomy.

METHODS

A literature search through PubMed, Embase, EBSCO, Cochrane database of systematic reviews, and Web of Science from its inception up to April 2019 using the following search keywords in various combinations: sternal, sternotomy, mediastinitis, deep sternal wound infection, cardiac surgery, closure.

RESULTS

Single wire fixation methods, at present, seems the most useful method to perform sternal closure in routine patients, although patients with a fragile sternum might benefit more from a figure-of-eight technique. In high-risk patients (e.g. chronic pulmonary disease, obesity, bilateral internal mammary artery harvesting, diabetes, off-midline sternotomy), rigid plate fixation is currently the most effective method, if available; alternatively, weave techniques could be used.

CONCLUSION

The choice among the sternal closure techniques should be mainly inspired and tailored on the patient's characteristics, and correct judgement and experience play a pivotal role. A decisional algorithm has been proposed as an attempt to overcome the absence of specific guidelines and to guide the operative approach. This operative approach might be used also in non-cardiac procedure in which median sternotomy is required, such as in case of thoracic surgery.

Single- versus multidose cardioplegia in adult cardiac surgery patients: A meta-analysis

OBJECTIVE

To compare outcomes of single (intervention group: del Nido [DN], and histamine-tryptophan-ketoglutarate) versus multidose (control group) cardioplegia in the adult cardiac surgery patients.

METHODS

Medical search engines were interrogated to identify relevant randomized controlled trials and propensity-score matched cohorts. Meta-analysis was conducted for primary (in-hospital/30-day mortality) and secondary (ischemic and cardiopulmonary bypass [CPB] times, reperfusion fibrillation, peak of cardiac enzymes, myocardial infarction) endpoints. Subgroup analyses were conducted for study design and type of intervention, and meta-regression for primary outcome included type of surgery and left ventricular ejection fraction as moderators.

RESULTS

Ten randomized controlled trials and 13 propensity-score matched cohorts were included, reporting on 5516 patients. Estimates are expressed as (parameter value [OR, odds ratio; MD, mean difference; SMD, standardized mean difference]/unit of measure [95% confidence interval], P value). DN reduced ischemic time (MD, -7.18 minutes [-12.52 to -1.84], P < .01), CPB time (MD, -10.44 minutes [-18.99 to -1.88], P .01), reperfusion fibrillation (OR, 0.16 [0.05-0.54], P < .01), and cardiac enzymes (SMD -0.17 [-0.29, 0.05], P < .01) compared with multidose cardioplegia. None of these beneficial effects were reproduced by histamine-tryptophan-ketoglutarate, which instead increased CPB time (MD, 2.04 minutes [0.73-3.37], P < .01) and reperfusion fibrillation (OR, 1.80 [1.20-2.70], P < .01). There was no difference in mortality and myocardial infarction between single and multidose, independently of type of surgery or left ventricular ejection fraction.

CONCLUSIONS

DN decreases operative times, reperfusion fibrillation, and surge of cardiac enzymes compared with multidose cardioplegia.

The use of allogenic and autologous tissue to treat aortic valve endocarditis

The surgical treatment of aortic valve endocarditis (AVE) is generally performed using conventional mechanical or biological xenograft prosthesis, with limited use of aortic homograft (Ao-Homo) or pulmonary autograft (PA). Clinical evidence has demonstrated a clear contradiction between the proven benefits of Ao-Homo and PA in the context of infection and the very limited use of allogenic or autologous tissue in everyday clinical practice. This review aims to summarize the most recent and relevant literature in order to foster the scientific debate on the use of the use of allogenic and autologous tissue to treat AVE. The decisional process of the Heart Team should also include the preferences of the patient, his/her family, the general cardiologist or primary care physician. The use of allogenic or autologous valve substitute is beneficial if there is a high risk of recurrence of infection, avoiding extensive adhesiolysis and debridement of synthetic material. In any case, those procedures should be performed by highly trained centers to optimize outcomes.

The Choice of Treatment in Ischemic Mitral Regurgitation With Reduced Left Ventricular Function

BACKGROUND

Ischemic mitral regurgitation is a condition characterized by mitral insufficiency secondary to an ischemic left ventricle. Primarily, the pathology is the result of perturbation of normal regional left ventricular geometry combined with adverse remodeling. We present a comprehensive review of contemporary surgical, medical, and percutaneous treatment options for ischemic mitral regurgitation, rigorously examined by current guidelines and literature.

METHODS

We conducted a literature search of the PubMed database, Embase, and the Cochrane Library (through November 2018) for studies reporting perioperative or late mortality and echocardiographic outcomes after surgical and nonsurgical intervention for ischemic mitral regurgitation.

RESULTS

Treatment of this condition is challenging and often requires a multimodality approach. These patients usually have multiple comorbidities that may preclude surgery as a viable option. A multidisciplinary team discussion is crucial in optimizing outcomes. There are several options for treatment and management of ischemic mitral regurgitation with differing benefits and risks. Guideline-directed medical therapy for heart failure is the treatment choice for moderate and severe ischemic mitral regurgitation, with consideration of coronary revascularization, mitral valve surgery, cardiac resynchronization therapy, or a combination of these, in appropriate candidates. The use of transcatheter mitral valve therapy is considered appropriate in high-risk patients with severe ischemic mitral regurgitation, heart failure, and reduced left ventricular ejection fraction, especially in those with hemodynamic instability.

CONCLUSIONS

The role of mitral valve surgery and transcatheter mitral valve therapy continues to evolve.

How to treat severe symptomatic structural valve deterioration of aortic surgical bioprosthesis: transcatheter valve-in-valve implantation or redo valve surgery?

The optimal management of aortic surgical bioprosthesis presenting with severe symptomatic structural valve deterioration is currently a matter of debate. Over the past 20 years, the number of implanted bioprostheses worldwide has been rapidly increasing at the expense of mechanical prostheses. A large proportion of patients, however, will require intervention for bioprosthesis structural valve deterioration. Current options for older patients who often have severe comorbidities include either transcatheter valve-in-valve (TVIV) implantation or redo valve surgery. The emergence of TVIV implantation, which is perceived to be less invasive than redo valve surgery, offers an effective alternative to surgery for these patients with proven safety and efficacy in high-risk patient groups including elderly and frail patients. A potential caveat to this strategy is that results of long-term follow-up after TVIV implantation are limited. Redo surgery is sometimes preferable, especially for young patients with a smaller-sized aortic bioprosthesis. With the emergence of TVIV implantation and the long experience of redo valve surgery, we currently have 2 complementary treatment modalities, allowing a tailor-made and patient-orientated intervention. In the heart team, the decision-making should be based on several factors including type of bioprosthesis failure, age, comorbidities, operative risk, anatomical factors, anticipated risks and benefits of each alternative, patient's choice and local experience. The aim of this review is to provide a framework for individualized optimal treatment strategies in patients with failed aortic surgical bioprosthesis.

Simulating the ideal geometrical and biomechanical parameters of the pulmonary autograft to prevent failure in the Ross operation

OBJECTIVES

Reinforcements for the pulmonary autograft (PA) in the Ross operation have been introduced to avoid the drawback of conduit expansion and failure. With the aid of an in silico simulation, the biomechanical boundaries applied to a healthy PA during the operation were studied to tailor the best implant technique to prevent reoperation.

METHODS

Follow-up echocardiograms of 66 Ross procedures were reviewed. Changes in the dimensions and geometry of reinforced and non-reinforced PAs were evaluated. Miniroot and subcoronary implantation techniques were used in this series. Mechanical stress tests were performed on 36 human pulmonary and aortic roots explanted from donor hearts. Finite element analysis was applied to obtain high-fidelity simulation under static and dynamic conditions of the biomechanical properties and applied stresses on the PA root and leaflet and the similar components of the native aorta.

RESULTS

The non-reinforced group showed increases in the percentages of the mean diameter that were significantly higher than those in the reinforced group at the level of the Valsalva sinuses (3.9%) and the annulus (12.1%). The mechanical simulation confirmed geometrical and dimensional changes detected by clinical imaging and demonstrated the non-linear biomechanical behaviour of the PA anastomosed to the aorta, a stiffer behaviour of the aortic root in relation to the PA and similar qualitative and quantitative behaviours of leaflets of the 2 tissues. The annulus was the most significant constraint to dilation and affected the distribution of stress and strain within the entire complex, with particular strain on the sutured regions. The PA was able to evenly absorb mechanical stresses but was less adaptable to circumferential stresses, potentially explaining its known dilatation tendency over time.

CONCLUSIONS

The absence of reinforcement leads to a more marked increase in the diameter of the PA. Preservation of the native geometry of the PA root is crucial; the miniroot technique with external reinforcement is the most suitable strategy in this context.

Transcatheter Tricuspid Valve Interventions: Current Approaches and Future Perspectives

Tricuspid valve regurgitation is generally functional in nature due to right-sided dysfunction in the setting of left-sided concomitant cardiac disease or pulmonary hypertension. Patients living with tricuspid regurgitation often experience numerous limitations as a result of right-sided heart failure symptoms. Patients with significant tricuspid disease, whether native, repaired, or replaced valve, often present with significant symptoms but may not be ideal candidates for operation or, eventually, reoperation. Transcatheter techniques to either repair or replace the tricuspid valve are a burgeoning frontier in structural cardiac interventions. Anatomical challenges include the large and asymmetrical annulus, paucity of calcification, adjacency of the right coronary artery system, and fragility of the valve tissue. Current approaches under investigation in feasibility and early phase clinical trials include edge-to-edge repair, coaptation enhancement, annuloplasty, heterotopic caval valve implantation, and percutaneous tricuspid valve replacement. Although there are limitations to the currently available transcatheter options for the patients, the initial data demonstrate the relative safety of using existing devices with good results and functional improvement. Hopefully, the emerging interest into interventional therapy of tricuspid valve disease will bring back the "forgotten valve" into the conscience of the cardiological and surgical community. This review intends to summarize the current strategies and evidences in transcatheter tricuspid valve intervention and enlightening new avenues for future clinical studies.

Mechanical circulatory support for refractory cardiogenic shock post-acute myocardial infarction-a decade of lessons

Background

There are 0.9 catheterization labs per 100,000 inhabitants in Scotland for percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI), which are much less accessible to patients in remote and rural areas. An uncommon but sinister sequalae following AMI is cardiogenic shock (CS) that could be refractory to inotropic support. CS complicates 5-15% of AMIs occurring in ST-segment elevation myocardial infarctions (STEMIs). Outcomes of CS are poor with mortalities of up to 90% reported in the literature in the absence of experienced care. We report our experience as the tertiary referral centre in Scotland for MCS and heart transplantation over 8 years.

Methods

A retrospective review of prospectively collected data was undertaken on all patients registered to the MCS service. The database was interrogated for patient demographics, type of mechanical circulatory support (MCS) and duration of MCS support, PCI-outcomes and survival to 30 days. A time-to-event analysis was performed using patient survival as the primary outcome measure.

Results

Twenty-three patients (16 male, 7 females) were included. The median age of the patients as 50 years (range, 45-56 years). VA-ECMO was the initial MCS of choice in 17 (73.9%) patients with BIVAD for 4 (17.4%) patients and LVAD for 2 (8.7%) patients. Thirty-day mortality was 21.8% in this cohort, however survival to discharge was 52.2%. Eleven (47.8%) patients recovered without the need for any further support, however only 9 (81.8%) patients in this subgroup survived to discharge. Three (13.0%) patients received a durable LVAD. In this subgroup, one patient was transplanted whereas two patients died due to complications while on support. The median length of in-hospital MCS support was 4 days. Median in-hospital stay was 27 days. Long-term follow up of up to 8 years demonstrates a high mortality beyond 30-day up to the first 6-month post MCS support.

Conclusions

MCS usage in these patients carries a high mortality in the early post-implantation period. However, there is a significant benefit to patients who survive the initial bridging period to recovery or destination therapy.

Clozapine-related Sudden Pericarditis in a Patient Taking Long Acting Aripiprazole and Valproate: A Case Report

Clozapine may be associated with cardiovascular adverse effects including QTc prolongation and, more rarely, with myocarditis and pericarditis. Although rare, these latter cardiovascular adverse effects may be life-threatening and must be immediately recognized and treated. Several cases of clozapine related-pericarditis have been described and often it has a subtle and insidious onset with symptoms that may be often misdiagnosed with psychiatric manifestations (e.g. anxiety, panic or somatization) leading to a delayed correct diagnosis with potential fatal consequences. In the present report we describe the case of a 27-year-old girl with schizoaffective disorder taking long acting aripiprazole and valproate who developed a sudden onset clozapine-related pericarditis during titration phase that resolved with immediate clozapine discontinuation and indomethacin administration. We underline the importance of an early diagnosis of clozapine-related pericarditis and the need to have monitoring protocols to prevent this potentially fatal adverse effect especially when polypharmacy is administered to patients taking clozapine.