Fractional flow reserve and instantaneous wave-free ratio in coronary artery bypass grafting: a meta-analysis and practice review

Objective

Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are invasive methods to assess the functional significance of intermediate severity coronary lesions. Both indexes have been extensively validated in clinical trials in guiding revascularisation in patients with stable ischaemic heart disease undergoing percutaneous coronary intervention (PCI) with improved clinical outcomes. However, the role of these tools in coronary artery bypass grafting (CABG) is less clear.

Methods

A meta-analysis of randomised trials and observational studies was carried out to help in determining the optimal strategy for assessing lesion severity and selecting graft targets in patients undergoing CABG. Electronic searches were carried out on Embase, MEDLINE, and Web of Science. A group of four authors independently screened and then assessed the retrieved records. Cochrane's Risk of Bias and Robins-I tools were used for bias assessment. A survey was conducted among surgeons and cardiologists to describe current attitudes towards the preoperative use of functional coronary investigations in practice.

Results

Clinical outcomes including mortality at 30 days, perioperative myocardial infarction, number of grafts, incidence of stroke, rate of further need for revascularisation, and patient-reported quality of life did not differ in CABG guided by functional testing from those guided by traditional angiography.The survey revealed that in half of the surgical and cardiology units functional assessment is performed in CABG patients; there is a general perception that functional testing has improved patient care and its use would clarify the role of moderate coronary lesions that often need multidisciplinary rediscussions; moderate stenosis are felt to be clinically relevant; and anatomical considerations need to be taken into account together with functional assessment.

Conclusions

At present, the evidence to support the routine use of functional testing in intermediate lesions for planning CABG is currently insufficient. The pooled data currently available do not show an increased risk in mortality, myocardial injury, and stroke in the FFR/iFR-guided group. Further trials with highly selected populations are needed to clarify the best strategy.

Systematic Review Registration

ClinicalTrials.gov, identifier (CRD42023414604).

Malpratice claims in cardiology and cardiac surgery: A medico-legal issue

Medical liability has become a challenge in every physician's modern practice with the consequent loss of the physician's autonomy and an increase in "defensive medicine". From this perspective, the role of Legal Medicine in assessing medical liability has become increasingly specific and a homogenization of the methods of ascertainment is increasingly necessary, since such a process can contribute to strengthening the guarantees in professional liability procedures. Focusing on malpractice claims in the field of cardiology, the complexity of the management of cardiac pathologies and the frequency of severe adverse events implies the importance of a multi-disciplinary approach, together with the application of a shared ascertainment methodology. In particular, it is essential for the forensic pathologist to collaborate with experts in cardio-pathology, cardiology and/or cardiac surgery in cases of alleged medical liability in the cardiologic field and to follow the guidelines which have been produced to assist the expert dealing with deaths reflecting cardiac disease, in order to prevent criticism of case analysis in medico-legal environments and to promote the standardization of the structure of the juridical-legislative medical malpractice lawsuits.

Cardiopulmonary exercise testing as a guideline indicator for mitral valve intervention

Background

Primary mitral regurgitation (MR) is one of the most common heart valvular pathologies. However, optimum timing of surgery remains controversial.

Purpose

To describe changes in cardiopulmonary exercise testing (CPET) parameters after surgery for severe primary MR.

Methods

In a single centre prospective study, patients undergoing surgery under current ESC guidelines for severe primary MR underwent assessment with transthoracic echocardiogram, CPET, cardiac MRI and quality of life questionnaire pre-operatively and at six months after surgery. The primary outcome was a per protocol analysis of impaired post-operative functional capacity (defined as post-operative left ventricular ejection fraction on transthoracic echocardiogram <50% and/or post-operative percentage predicted peak VO2 ≤84%).

Results

43 of the 50 patients recruited between February 2017 and October 2018 were included in the per protocol analysis. Thirty five patients (72.9%) had impaired post-operative functional capacity. In the overall cohort (n=43), there was a significant fall post-operatively in percentage predicted peak VO2 (ppVO2) (81.8±15.7% vs. 76.2±16.2%, p<0.01) and anaerobic threshold (AT) (48.0±11.1% vs. 44.3±10.1%, p=0.01). In patients with a class I indication for surgery (n=30), there was no significant change post-operatively in ppVO2 (79.6±15.7% vs. 75.6±16.7%, p=0.09) or AT (49.9±11.4% vs. 46.4±10.2%, p-0.09). However, in patients with a class II indication for surgery (n=13), there was a significant change post-operatively in ppVO2 (86.9±15.1% vs. 77.4±15.9%, p<0.01), but not in AT (43.5±9.6% vs. 39.5±8.3%, p=0.16).

In the multivariable analysis, pre-operative left ventricular ejection fraction ≤60% (hazard ratio, 1.69; 95% confidence interval, 1.56 to 480.1, p=0.04) and pre-operative percentage predicted peak VO2 ≤84% (hazard ratio, 1.22; 95% confidence interval, 2.13 to 107.1, p<0.01) were independent predictors for impaired post-operative functional capacity.

Conclusions

Pre-operative percentage predicted peak VO2 ≤84% is an independent predictor of impaired post-operative functional capacity. Subject to a confirmatory study, this may help to refine current ESC guidelines for intervention for severe primary MR.

Change in ppVO2 after surgery

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Rosetrees Trust and Friends of Hammersmith Hospital

Robotics in cardiac surgery

A summary of its uses in mitral valve surgery and coronary artery revascularisation.

Off-pump versus on-pump revascularization in females: a meta-analysis of observational studies

BACKGROUND

Coronary revascularization in female patients presents several challenges, including smaller target vessels and smaller conduits. Furthermore, late presentation and more co-morbidities than males may increase complication rates. The aim of this study was to assess whether off-pump coronary artery bypass (OPCAB) improves outcomes when compared to on-pump coronary artery bypass (ONCAB) in the female population.

METHODS

A systematic literature review identified six observational studies, incorporating 23313 patients (n=9596 OPCAB, 13717 ONCAB). These were meta-analyzed using random effects modeling. Heterogeneity, subgroup analysis, quality scoring and publication bias were assessed. The primary endpoints were 30-day mortality and major cardiac, respiratory and renal complications. Secondary endpoints were the number of grafts per patient.

RESULTS

No statistically significant difference was observed in 30-day mortality between the OPCAB and ONCAB groups (4.8% vs. 0.7%; OR 0.96; 95% CI [0.41, 2.24], p=0.92). Significant inter-study heterogeneity was also present (I2=94%) and was not explained by study size or quality. Peri-operative myocardial infarction (OR 0.65; 95% CI [0.51, 0.84], p=0.0009) was significantly lower with OPCAB without significant heterogeneity; however, OPCAB did not significantly alter other morbidity outcomes. OPCAB was associated with a trend towards fewer grafts per patient than ONCAB.

CONCLUSIONS

OPCAB is a safe alternative to ONCAB in the surgical revascularisation of female patients and may reduce post-operative myocardial infarction (MI). However, this does not translate into a reduction in 30-day mortality and OPCAB does not significantly improve other cardiovascular, renal or neurological outcomes. Late outcome data remains lacking and a well-structured, randomized trial is required to answer vital questions regarding the effect of OPCAB on women in the long-term.

Cardiac robotics: a review and St. Mary's experience

BACKGROUND

The introduction of the laparoscope led to the progress of surgery to a new era, where surgeries that were deemed major are now being performed through keyhole incisions with comparable outcomes to open surgery. However, with this new technique rose several problems like inaccurate depth perception, diminished tactile feedback, need for experienced assistance, and reduction in degrees of motion of the surgeons hands all of which inspired surgeons and engineers to look for mechanical tools to help in reducing these problems. Henceforth; came the application of robotics in surgery.

METHODS

A PubMed and Medline search was performed on cardiac robotic surgery and its applications in mitral valve repair and coronary artery surgery. A total of twenty one articles were picked that allude to the subject. A history of robotic surgery was outlined followed by applications of robotic manipulation in cardiac surgery was narrated. A quick overview of this technology in telemedicine was then outlined followed by future prospects of this technology in surgery was contemplated.

RESULTS

The experience of the group from St. Mary's Hospital, London in this field was outlined. During the period of 4 years a total of 102 cases of robotic cardiac surgery were performed. The mean length of hospital stay was 3.1 days with a standard deviation of 1.4 days and the morbidity of the series explained. There was no mortality.

CONCLUSION

Early studies have shown that minimally invasive cardiac surgery is feasible and yields results similar to conventional cardiac surgery, yet it is more technically demanding on the surgeon. As advantageous as this new modality is, further multicenter studies are needed to prove its efficacy.

Treatment of poisoning induced cardiac impairment using cardiopulmonary bypass: a review

Severe poisoning can cause potentially fatal cardiac depression. Cardiopulmonary bypass (CPB) can support the depressed myocardium, but there are no clear indications or guidelines available on its use in severe poisoning. A review was conducted of relevant papers in the available literature (seven single case reports of both deliberate and accidental ingestion of cardiotoxic drugs and two animal studies). Although CPB is rarely used in the management of poisoning, it may have potential benefits for haemodynamic instability not responding to conventional measures. At present there is insufficient evidence concerning the use of CPB as a treatment for severe cardiac impairment due to poisoning (grade C). This review suggests that in patients with severe and potentially prolonged reversible cardiotoxicity there is potential for full survival with CPB, provided that the patient has not already sustained hypoxic cerebral damage due to resistant hypotension prior to its use.

Minimal access coronary revascularisation without cardiopulmonary bypass—the impact of robotic technology in the current clinical practice

Recent advances in interventional cardiology and cardiac surgery have changed the traditional therapeutic algorithms by altering indications, timing and patterns of referral for subsequent surgical treatment. The traditional longitudinal sternomy incision has been the surgical approach of choice for multi-vessel coronary revascularisation. Drawbacks of this incision include potential postoperative morbidity, which translates to a prolonged postoperative length of stay. The combination of minimally invasive direct coronary artery bypass (MIDCAB) with percutaneous transluminal coronary angioplasty (PTCA) or stenting (a hybrid approach) is an alternative therapeutic method for patients with multivessel coronary artery disease. Recent advances in percutaneous interventions have attempted to address the problem of re-stenosis, initially through the deployment of bare metal intra-coronary stents and, more recently, with drug-eluting stents. Developments in coronary revascularisation have focused on reducing both surgical invasiveness and trauma. Patients with significant co-morbid pathologies, the ones undergoing re-interventions, and especially the elderly may benefit from such hybrid procedures by avoiding cardiopulmonary bypass and midline sternotomy. Minimally invasive techniques have revolutionized cardiothoracic surgery by increasing patient satisfaction and by reducing surgical trauma, hospital stay and consequently overall costs. There are however limitations. Robot assisted surgery endeavours to minimise these technical hindrances and so allow better and more accurate surgical practice whilst minimising surgical trauma.

Aorto-right atrial fistula associated with native tricuspid valve endocarditis

Abnormal connections between the ascending aorta and the cardiac chambers are rare. Most are due to ruptured aneurysms of the sinus of Valsalva. Congenital fistulae between the aorta and left atrium are described. We report a case of native tricuspid valve endocarditis associated with a fistula between the right atrium and the aorta.

Heterotopic heart transplantation through a right thoracotomy

Heterotopic heart transplantation was performed via a right thoracotomy in a patient with elevated pulmonary vascular resistance and previous coronary artery bypass grafting using both internal mammary arteries. The right thoracotomy approach is the safest way to approach the native heart while preserving the patent grafts.

A prospective randomized trial of complete atrioventricular transplantation versus ventricular transplantation with atrioplasty

BACKGROUND

The standard technique of ventricular transplantation with atrioplasty (SOHT) distorts atrial anatomy. This may compromise diastolic ventricular function, impair atrioventricular valve competence and elevate resting ANP secretion. In contrast, complete atrioventricular anastomosis (CAVT) preserves atrial geometry.

METHODS

We evaluated long term outcome in a prospective randomized trial of CAVT vs. SOHT. The primary outcome measures were peak oxygen uptake, atrioventricular valve regurgitation and ANP secretion.

RESULTS

58 recipients (median age 49 years; range 21-64) were consecutively randomized (29 CAVT; 29 SOHT). There were no differences in total ischaemic time, cardiopulmonary bypass time, postoperative bleeding or immunosuppression. Cardiopulmonary exercise tolerance testing was performed by 29 recipients at 742 to 1825 days. Pulmonary function was equivalent. Peak oxygen consumption expressed as a percentage of predicted maximum was 53.5% with CAVT and 63.8% with SOHT (p = 0.14). Echocardiography was performed on 41 recipients at 944 to 1665 days. There was less tricuspid regurgitation with CAVT (3/22 [13.6%] CAVT vs. 10/19 [52.6%] SOHT; p = 0.019). The incidence of mitral regurgitation was similar (5/22 [22.7%] CAVT vs. 4/19 [21.1%] SOHT; p = 0.803). Resting ANP secretion was assessed in 17 recipients at 1013 to 1812 days. All were hemodynamically stable and none had concurrent rejection. Resting ANP secretion was less with CAVT (CAVT: 283 pg/ml; SOHT: 521.4; p = 0.041).

CONCLUSIONS

Peak oxygen consumption was not influenced by implantation technique. However, CAVT reduced the incidence of tricuspid regurgitation and attenuated the elevation in resting ANP secretion.

The aortic valve after heart transplantation

We studied the aortic root (wall, semilunar cusp, septal myocardium) in 37 patients (29 male and 8 female; mean age; 41 years) who died 2 to 4,380 days (mean, 398 days) after heart (n = 34) and heart-lung (n = 3) transplantation. The aim of the study was to assess tissue viability, graft-host biological interaction, and cusp mineralization with time. Study methods included gross inspection and photos of each specimen, microradiography, histology and immunohistochemistry, scanning and transmission electron microscopy, and atomic absorption spectroscopy. There were no cases of valve dysfunction; in particular, cusp tears or perforations never occurred. Only 1 valve, in place for 12 years, had a pin-point calcification visible to the naked eye. Optimal preservation of the tissue components (endothelium, fibroblasts, collagen and elastic fibers, proteoglycans, intrinsic nervous ganglia) was observed at both short and long term. Concomitant acute rejection of valve leaflets and myocardium was seen in 7, mild valve thickening in 14, myxoid degeneration in 4, and graft aortic atherosclerosis in 26. Mineralization was negligible and was not progressive with time. No linear correlation was found between mineralization and number of acute rejections. In conclusion, we observed optimal cusp viability and integrity even at long term, concomitant valve and myocardium rejection with no valvular sequelae, and negligible, non-progressive cusp calcification. Donor-recipient blood group matching, heart-beating donor, and chronic immunosuppression are the reasonable explanations of the optimal durability of the aortic valve after heart transplantation.

Mid-term results of heart transplantation in diabetic patients

BACKGROUND

Diabetes mellitus (DM) has been considered a relative contraindication to heart transplantation (HTx) because of possible increased infection rates and worsening DM with prednisone immunosuppression. The introduction of cyclosporine has allowed us to reduce the dosage of oral steroids and to accept DM patients (pts) for HTx. We reviewed the mid-term outcome of our DM pts who had undergone HTx.

MATERIALS AND METHODS

Out of 257 HTx recipients, 19 males and 3 females, aged 53 +/- 8 years, were diabetic. Prior to HTx, DM was controlled with insulin in 5, with oral hypoglycemic agents in 7 and with diet in the remaining patients. Immunosuppression consisted of cyclosporine and azathioprine; low-dose prednisone was added in 10 patients because of repeated rejections.

RESULTS

All patients survived HTx and were followed 2 to 75 (mean 38 +/- 21) months. There were 4 late deaths, with actuarial survival of 84% at 5 years. DM was more difficult to control after HTx (12 patients requiring insulin vs 5 pre-HTx), but comparison of diabetic vs non diabetic patients following HTx showed no significant difference in frequency of rejection or infection during the 1st year (2.6 +/- 1.6 vs 2.1 +/- 1.5; 0.5 +/- 0.4 vs 0.4 +/- 0.3 episode/patient respectively) and in 5-year actuarial survival (84% vs 77%). Renal function is preserved in all DM patients, hypertension has developed in 11/18 (61%); annual post-HTx cardiac catheterisation has shown normal graft function and coronary arteries in all but 2 patients.

CONCLUSIONS

Mid-term results indicate that HTx can be safely performed in diabetic patients; a longer follow-up is required to determine whether DM is no longer a contraindication to HTx.

Results of heart transplantation by extending recipient selection criteria

From November 1985 to July 1993, 29 out of 241 patients (12%) who underwent heart transplantation (HTx) at our institution had one or more "classical" contraindications to HTx: age > or = 60 years (20 patients); insulin-dependent diabetes mellitus (5 patients); irreversible renal failure requiring combined heart-kidney transplantation (2 patients); previous surgery for malignancy (1 patient); familial hypercholesterolemia (1 patient) and active systemic infection (1 patient). The main indication for HTx was ischemic cardiomyopathy (21 patients, 61%). Immunosuppression regimen consisted of Cyclosporine and Azathioprine, oral prednisone being subsequently added in 6 patients because of persistent rejection. There were 2 perioperative deaths and one late death. Follow-up ranged from 1 to 88 months (mean, 28 +/- 20) with an actuarial survival at 5 years of 85 +/- 8%. Annual cardiac catheterization demonstrated normal graft function and coronary arteries in all. No significant differences in survival, incidence of rejection and infection, renal function and duration of hospitalization were found when these patients were compared with those with no contraindications to HTx. In conclusion, HTx can be performed with good early clinical results in selected patients with "classical" contraindications to HTx; longer follow-up, however, is needed to confirm whether extension of the recipient selection criteria justified.

Cardiac fibroma and heart transplantation

Successful orthotopic heart transplantation was performed in a 38-day-old child with a fetal echocardiographic diagnosis of a left ventricular mass and in a 40-year-old woman with cardiac murmur since childhood and an echocardiographic diagnosis of asymmetric septal hypertrophy. Pathologic examination of the removed hearts, consisting of gross, histologic, immunohistochemical, and ultrastructural studies, led to the final diagnosis of cardiac fibroma. Both patients were alive and in good condition at 35 and 28 months, respectively, after operation.

[Acute rejection: the diagnostic and therapeutic problems]

Acute allograft rejection is still a leading cause of both early and late mortality and morbidity after cardiac transplantation. Besides cell-mediated acute rejection, a "humoral" form exists which is more frequent in younger patients in the early postoperative period, and less likely to respond to the usual therapy. Cyclosporine therapy has deeply affected the clinical, laboratory and histological aspects of acute rejection. Though endomyocardial biopsy remains the most reliable diagnostic tool, other noninvasive procedures are of great value for a final diagnosis; among these are electrocardiography and two-dimensional echocardiography, which are the two elective techniques for post-transplantation follow-up in children. The laboratory and immunological assays, on the contrary, share a very low specificity. In conclusion, the diagnosis of acute rejection is still a clinical one, though supported by laboratory and histological evidence. In our experience, the natural evolution of many mild and mild-moderate rejection episodes toward regression does not support an excessive prophylaxis or an early treatment of symptom-free acute rejection. In addition, treatment of rejection must be personal and specific to each patient.