A novel transit-time flow metric, diastolic resistance index, detects subcritical anastomotic stenosis in coronary artery bypass grafting

Objective

Transit time flow measurement (TTFM) can detect critical anastomotic stenosis during coronary artery bypass grafting. However, the identification of subcritical stenosis remains challenging. We hypothesized that diastolic resistance index (DRI), a novel TTFM metric, is more effective in evaluating subcritical stenosis than the currently available TTFM metrics. DRI is used to measure changes in the diastolic versus systolic resistance of distal anastomosis.

Methods

A total of 123 coronary bypass anastomoses in 35 patients were prospectively analyzed. During coronary artery bypass grafting, the mean graft flow (Q_mean), pulsatility index, and diastolic filling were obtained. DRI was calculated using the intraoperative recordings of TTFM and arterial pressure. Postoperatively, stenosis of anastomoses was categorized into successful (<50%), subcritical (50%-74%), and critical (≥75%) via multidetector computed tomography scan.

Results

In total, 93 (76%), 13 (10%), and 17 (14%) anastomoses were graded as successful, subcritical, and critical, respectively. DRI and diastolic filling could distinguish subcritical from successful anastomoses (P < .01 and < .01, respectively), whereas Q_mean and pulsatility index could not (P = .12 and .39, respectively). The receiver operating characteristic curves were established to evaluate the diagnostic ability for detecting ≥50% stenosis. In left anterior descending artery grafting (n = 55), DRI had the highest area under the curve (0.91), followed by diastolic filling (0.87), Q_mean (0.74), and pulsatility index (0.65).

Conclusions

DRI and diastolic filling had a reliable diagnostic ability for detecting ≥50% stenosis during coronary artery bypass grafting. In left anterior descending artery grafting, DRI had a more satisfactory detection capability than other TTFM metrics.

Imaging neurovascular, endothelial and structural integrity in preparation to treat small vessel diseases. The INVESTIGATE-SVDs study protocol. Part of the SVDs@Target project

Background

Sporadic cerebral small vessel disease (SVD) and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) share clinical and neuroimaging features and possibly vascular dysfunction(s). However few studies have included both conditions, assessed more than one vascular dysfunction simultaneously, or included more than one centre. The INVESTIGATE-SVDs study will assess several cerebrovascular dysfunctions with MRI in participants with sporadic SVD or CADASIL at three European centres.

Methods

We will recruit participants with sporadic SVDs (ischaemic stroke or vascular cognitive impairment) and CADASIL in Edinburgh, Maastricht and Munich. We will perform detailed clinical and neuropsychological phenotyping of the participants, and neuroimaging including structural MRI, cerebrovascular reactivity MRI (CVR: using carbon dioxide challenge), phase contrast MRI (arterial, venous and CSF flow and pulsatility), dynamic contrast-enhanced MRI (blood brain barrier (BBB) leakage) and multishell diffusion imaging. Participants will measure their blood pressure (BP) and its variability over seven days using a telemetric device.

Discussion

INVESTIGATE-SVDs will assess the relationships of BBB integrity, CVR, pulsatility and CSF flow in sporadic SVD and CADASIL using a multisite, multimodal MRI protocol. We aim to establish associations between these measures of vascular function, risk factors particularly BP and its variability, and brain parenchymal lesions in these two SVD phenotypes. Additionally we will test feasibility of complex multisite MRI, provide reliable intermediary outcome measures and sample size estimates for future trials.

The influence of antisperm antibodies, intratesticular haemodynamics and the surgical approach to varicocelectomy on seminal variables

Objective

To evaluate the effect of antisperm antibodies (ASAs), hormonal levels, intratesticular haemodynamics and the surgical approach on the outcomes of varicocelectomy in infertile men, as assessed by seminal variables.

Patients and methods

In a prospective case-series study, 82 infertile men with varicocele (35 left and 47 bilateral) were evaluated. The preoperative assessment included a physical examination, semen analysis, assessment of ASAs in seminal plasma, hormonal levels (follicle-stimulating hormone (FSH), luteinising hormone and testosterone), and scrotal colour Doppler ultrasonography (CDUS) to measure the peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI) and pulsatility index. Patients were scheduled for varicocelectomy, with high ligation (Palomo) used in 40 patients (18, 45%, with left and 22, 55%, with bilateral varicocele), or an inguinal approach (Ivanissivich) with loupe magnification used in 42 (17, 40%, with left and 25, 60%, with bilateral varicocele). The men were reassessed at ⩾3 months after surgery and according to the improvement in seminal variables (expressed as a ⩾50% increase in total motile sperm count, TMSC), patients were further categorised into ‘improved’ or ‘unimproved’. Binary logistic regression analysis was used to investigate the predictors of improvement.

Results

Before surgery the ASAs were positive in 17 men (21%). There was no significant difference between the right and left sides in intratesticular haemodynamics. The TMSC was improved in 52 (63%) patients who had a significant improvement in the haemodynamic variables. Intratesticular haemodynamics, serum FSH and testosterone levels differed significantly between the improved and unimproved patients. Positivity for ASAs, the surgical approach and laterality of the varicocele were not significantly different, although the ASA-positive cases were characterised by a significant decrease in motility. Logistic regression analysis showed that the EDV, PSV, FSH, testosterone level and bilateral testicular volume (BTV) were significant predictors of improvement.

Conclusion

Positivity for ASAs is not a predictor of the outcome after varicocelectomy but affects only the motile fraction in positive cases, despite the improvement in other seminal variables and testicular haemodynamics, and regardless of the surgical approach. The EDV, PSV, FSH, testosterone and BTV were significant predictors of a successful outcome.

Perioperative monitoring in liver transplant patients

Liver transplant (LT) is a major surgical undertaking involving major fluid shifts, hemodynamic instability and metabolic derangements in a patient with preexisting liver failure and multisystemic derangements. Monitoring and organ support initiated in the preoperative phase is continued intraoperatively and into the postoperative phase to ensure an optimal outcome. As cardiovascular events are the leading cause of non-graft related death among LT recipients, major emphasis is placed on cardiovascular monitoring. The other essential monitoring are the continuous assessment of coagulapathy, extent of metabolic derangements, dyselectrolytemis and intracranial pressure monitoring in patients with fulminant hepatic failure. The type and extent of monitoring differs with need according to preexisting child status of the patient and the extent of systemic derangements. It also varies among transplant centers and is mainly determined by individual or institutional practices.