Design and characteristics of the prophylactic intra-operative ventricular arrhythmia ablation in high-risk LVAD candidates (PIVATAL) trial

BACKGROUND

The use of a Left Ventricular Assist Device (LVAD) in patients with advanced heart failure refractory to optimal medical management has progressed steadily over the past two decades. Data have demonstrated reduced LVAD efficacy, worse clinical outcome, and higher mortality for patients who experience significant ventricular tachyarrhythmia (VTA). We hypothesize that a novel prophylactic intra-operative VTA ablation protocol at the time of LVAD implantation may reduce the recurrent VTA and adverse events postimplant.

METHODS

We designed a prospective, multicenter, open-label, randomized-controlled clinical trial enrolling 100 patients who are LVAD candidates with a history of VTA in the previous 5 years. Enrolled patients will be randomized in a 1:1 fashion to intra-operative VTA ablation (n = 50) versus conventional medical management (n = 50) with LVAD implant. Arrhythmia outcomes data will be captured by an implantable cardioverter defibrillator (ICD) to monitor VTA events, with a uniform ICD programming protocol. Patients will be followed prospectively over a mean of 18 months (with a minimum of 9 months) after LVAD implantation to evaluate recurrent VTA, adverse events, and procedural outcomes. Secondary endpoints include right heart function/hemodynamics, healthcare utilization, and quality of life.

CONCLUSION

The primary aim of this first-ever randomized trial is to assess the efficacy of intra-operative ablation during LVAD surgery in reducing VTA recurrence and improving clinical outcomes for patients with a history of VTA.

Outcomes of del Nido cardioplegia after surgical aortic valve replacement and coronary artery bypass grafting

OBJECTIVE

The use of del Nido cardioplegia (DNC) was initially adopted in the field of pediatric cardiac surgery. Several studies in adult patients suggested there were no differences in early postoperative outcomes as compared to blood-based cardioplegia. We sought to evaluate the impact of DNC as compared to modified Buckberg cardioplegia (BC) on early postoperative outcomes in patients undergoing surgical aortic valve replacement with and without coronary artery bypass grafting (SAVR ± CABG).

METHODS

All SAVR ± CABG procedures were switched from BC to DNC at our institute in 2012. We compared outcomes of BC (November 2007-October 2012; n = 1037) with DNC (November 2012-December 2017; n = 1067). Significant baseline differences were observed between the two groups and such differences were adjusted via inverse propensity treatment weighting.

RESULTS

After adjustment, SAVR ± CABG patients who received DNC required longer aortic cross-clamp times, while postoperative peak troponin I and creatinine kinase-MB isotype were significantly lower in the BC group. Length of hospital and intensive care unit stay were significantly shorter in the DNC group. The incidence of postoperative complications was lower in the DNC cohort. Thirty-day mortality rate was significantly lower in the DNC group (3.0% vs 4.9%, p = 0.002).

CONCLUSIONS

The use of DNC cardioplegia in our cohort of adult patients who underwent SAVR ± CABG was safe and associated with improved postoperative outcomes. However, the use of DNC may be associated with higher degrees of myocardial injury.

Clinical Profile and Outcomes of Patients With Pure Aortic Regurgitation Who Underwent Surgical Aortic Valve Replacement

Surgical aortic valve replacement (SAVR) remains the standard of care for patients with chronic severe aortic regurgitation (AR). The introduction of a dedicated transcatheter heart valve for AR has fueled interest in using transcatheter aortic valve replacement to treat patients with isolated AR. We aimed to characterize the profile and outcomes of patients with symptomatic severe AR who underwent isolated SAVR. We conducted a retrospective, observational study of patients who underwent isolated SAVR for symptomatic severe AR at our institution. The primary outcome was in-hospital all-cause mortality. Patients were followed up with 30-day clinical and echocardiographic assessment. A total of 979 patients who underwent SAVR for severe AR between January 2015 and June 2021 were screened for eligibility, of whom 112 patients (11.4%) underwent isolated SAVR for symptomatic severe AR and were included in this analysis. Approximately 25% of patients were deemed to be at intermediate or high risk (n = 26 of 112). The primary outcome occurred in 2.7% of patients (n = 3 of 112). In-hospital stroke occurred in 2.7% of patients (n = 3 of 112), and new-onset atrial fibrillation occurred in 32.1% (n = 36 of 112). At 30-day follow-up, all-cause mortality occurred in 3.6% of patients (n = 4 of 112), and 0.8% (1 of 112) had >mild AR. In conclusion, in a tertiary referral center, the number of patients who underwent isolated SAVR for pure AR represented a small fraction of the overall SAVR patients. The vast majority were low risk and younger when compared with patients with severe aortic stenosis. SAVR yielded excellent short-term mortality and echocardiographic improvements.

Effects of Body Mass Index on Presentation and Outcomes of COVID-19 among Heart Transplant and Left Ventricular Assist Device Patients: A Multi-Institutional Study

The coronavirus disease 2019 (COVID-19) pandemic continues to pose a significant threat to patients receiving advanced heart failure therapies. The current study was undertaken to better understand the relationship between obesity and outcomes of SARS-CoV-2 infection in patients with a left ventricular assist device (LVAD) or heart transplant. We performed a retrospective review of patients with a heart transplant or LVAD who presented to one of the participating 11 institutions between April 1 and November 30, 2020. Patients were grouped by body mass index (BMI) into obese (BMI ≥ 30 k/m2) and nonobese cohorts (BMI < 30 kg/m2). Multivariable logistic regression models were used to estimate effects of obesity on outcomes of interest. Across all centers, 162 heart transplant and 81 LVAD patients were identified; 54 (33%) and 38 (47%) were obese, respectively. Obese patients tended to have more symptoms at presentation. No differences in rates of hospitalization or ICU admission were noted. Obese patients with LVADs were more likely to require mechanical ventilation (39% vs. 8%, p < 0.05). No differences in renal failure or secondary infection were noted. Mortality was similar among heart transplant patients (11% [obese] vs. 16% [nonobese], p = 0.628) and LVAD patients (12% vs. 15%, p = 1.0). BMI was not associated with increased adjusted odds of mortality, ICU admission, or mechanical ventilation (all p > 0.10). In summary, acute presentations of SARS-CoV-2 among heart transplant and LVAD recipients carry a significantly higher mortality than the general population, although BMI does not appear to impact this. Further studies on the longer-term effects of COVID-19 on this population are warranted.

Overview of the FDA's Circulatory System Devices Panel virtual meeting on the TransMedics Organ Care System (OCS) Heart - portable extracorporeal heart perfusion and monitoring system

There are a limited number of donor hearts available for transplantation every year, and an even lower number of these hearts actually undergo transplantation. One of the barriers to utilizing donor hearts is the inferior outcomes associated with prolonged ischemic times. There have been increasing attempts to develop alternative techniques for prolonged storage to raise the number of heart transplants while maintaining acceptable outcomes. One such new technology utilizes continuous ex vivo perfusion of the donor heart with oxygenated blood and allows for prolonged storage and preservation times. The TransMedics Organ Care System (OCS) Heart (TransMedics; Andover, MA) claims to optimize the condition of the donor organs by preserving them in a warm, functioning environment. On April 6, 2021, the United States Food and Drug Administration convened a virtual meeting of the Circulatory System Devices Panel of the Medical Devices Advisory Committee to provide guidance on the TransMedics OCS Heart System's application for premarket approval. This application was subsequently approved on September 7, 2021. We provide an overview of the meeting, including the results of the clinical trials that were presented.

Beta-blockers and Ambulatory Inotropic Therapy

BACKGROUND

Continuous infusion of ambulatory inotropic therapy (AIT) is increasingly used in patients with end-stage heart failure (HF). There is a paucity of data concerning the concomitant use of beta-blockers (BB) in these patients.

METHODS

We retrospectively reviewed all patients discharged from our institution on AIT. The cohort was stratified into 2 groups based on BB use. The 2 groups were compared for differences in hospitalizations due to HF, ventricular arrhythmias and ICD therapies (shock or antitachycardia pacing).

RESULTS

Between 2010 and 2017, 349 patients were discharged on AIT (95% on milrinone); 74% were males with a mean age of 61 ± 14 years. BB were used in 195 (56%) patients, whereas 154 (44%) did not receive these medications. Patients in the BB group had longer duration of AIT support compared to those in the non-BB group (141 [1-2114] vs 68 [1-690] days). After adjusting for differences in baseline characteristics and indication for AIT, patients in the BB group had significantly lower rates of hospitalizations due to HF (hazard ratio [HR] 0.61 (0.43-0.86); P = 0.005), ventricular arrhythmias (HR 0.34 [0.15-0.74]; P = 0.007) and ICD therapies (HR 0.24 [0.07-0.79]; P = 0.02).

CONCLUSION

In patients with end-stage HF on AIT, the use of BB with inotropes was associated with fewer hospitalizations due to HF and fewer ventricular arrhythmias.

From Hip to Heart: A Comprehensive Evaluation of an Infiltrative Cardiomyopathy

Infiltrative cardiomyopathies are an increasingly recognized cause of heart failure warranting systematic evaluation. Given overlap of clinical and imaging findings among etiologies of infiltrative cardiomyopathies, comprehensive evaluation, including a history and physical examination, advanced cardiac imaging, and sometimes endomyocardial biopsy, is required for diagnosis. We report a case of infiltrative cardiomyopathy in which endomyocardial biopsy confirmed diagnosis of cobalt-induced cardiomyopathy. The novel teaching points highlighted by this case report include identification of heavy-metal toxicity as a cause of infiltrative cardiomyopathy, and the outline of a diagnostic approach and management for cobalt-induced cardiomyopathy.

Outcomes in patients with smaller body surface area after HeartMate 3 left ventricular assist device implantation

BACKGROUND

Due to anatomic and physiologic concerns, prior generations of the left ventricular assist devices (LVAD) have frequently been denied to patients with small body size. However, outcomes in patients with small body surface area (BSA) following HeartMate 3 (HM3) LVAD implantation remain relatively unknown.

METHODS

A cohort of 220 patients implanted at a single center was divided into two groups: BSA ≤1.8 m² (small BSA, n = 37) and BSA >1.8 m² (large BSA, n = 183). We investigated baseline characteristics and clinical outcomes including survival and incidence of adverse events.

RESULTS

Small BSA patients were older (60 vs. 57 years), more likely female (60% vs. 20%), had a lower body mass index (24 vs. 32 kg/m² ), lower incidence of diabetes (32% vs. 51%), history of stroke (5% vs. 19%), and left ventricular thrombus (0% vs. 11%). They had smaller left ventricular end diastolic diameter (64.8 vs. 69.3 mm). Pump speed and pump flows at discharge were lower in the small BSA group. Survival at 1 year and 2 years was 86% versus 87% and 86% versus 79% for small versus large BSA groups (p = 0.408), respectively. The rates of adverse events were similar between groups and there were no cases of confirmed pump thrombosis. The incidence of readmissions for low flow alarms was higher in the small BSA group (0.55 vs. 0.24 EPPY).

CONCLUSIONS

These findings demonstrate comparable outcomes in patients with small body size and suggest that this parameter should not be an exclusion criterion on patients who are otherwise candidates for HM3 LVAD implantation.

Characteristics and Outcomes of Patients with Inflammatory Cardiomyopathies Receiving Mechanical Circulatory Support: An STS-INTERMACS Registry Analysis

BACKGROUND

Durable mechanical circulatory support (MCS) therapy improves survival in patients with advanced heart failure. Knowledge regarding the outcomes experienced by patients with inflammatory cardiomyopathy (CM) who receive durable MCS therapy is limited.

METHODS AND RESULTS

We compared patients with inflammatory CM with patients with idiopathic dilated CM enrolled in the STS-INTERMACS registry. Among 19,012 patients, 329 (1.7%) had inflammatory CM and 5978 had idiopathic dilated CM (31.4%). The patients with inflammatory CM were younger, more likely to be White, and women. These patients experienced more preoperative arrhythmias and higher use of temporary MCS. Patients with inflammatory CM had a higher rate of early adverse events (<3 months after device implant), including bleeding, arrhythmias, non-device-related infections, neurologic dysfunction, and respiratory failure. The rate of late adverse events (≥3 months) was similar in the 2 groups. Patients with inflammatory CM had a similar 1-year (80% vs 84%) and 2-year (72% vs 76%, P = .15) survival. Myocardial recovery resulting in device explant was more common among patients with inflammatory CM (5.5% vs 2.3%, P < .001).

CONCLUSIONS

Patients with inflammatory CM who received durable MCS appear to have a similar survival compared with patients with idiopathic dilated CM despite a higher early adverse event burden. Our findings support the use of durable MCS in an inflammatory CM population.

Intra-Aortic Balloon Pump as a Bridge to Durable Left Ventricular Assist Device

Left ventricular assist devices (LVAD) are increasingly being used as destination therapy in patients with Stage D heart failure. It has been reported that a majority of patients who receive a durable LVAD (dLVAD) present in cardiogenic shock due to decompensated heart failure (ADHF‐CS). As it stands, there is no consensus on the optimal management strategy for patients presenting with ADHF. Bridging with intra‐aortic balloon pumps (IABPs) continues to be a therapeutic option in patients with hemodynamic instability due to cardiogenic shock. The majority of data regarding the use of IABP in cardiogenic shock come from studies in patients presenting with acute myocardial infarction with cardiogenic shock and demonstrates that there is no benefit of routine IABP use in this patient population. However, the role of IABPs as a bridge to dLVAD in ADHF‐CS has yet to be determined. The hemodynamic changes seen in acute myocardial infarction with cardiogenic shock are known to be different and more acutely impaired than those presenting with ADHF‐CS as evidenced by differences in pressure/volume loops. Thus, data should not be extrapolated across these 2 very different disease processes. The aim of this review is to describe results from contemporary studies examining the use of IABPs as a bridge to dLVAD in patients with ADHF‐CS. Retrospective evidence from large registries suggests that the use of IABP as a bridge to dLVAD is feasible and safe when compared with other platforms of temporary mechanical circulatory support. However, there is currently a paucity of high‐quality evidence examining this increasingly important clinical question.

The Society of Thoracic Surgeons Intermacs 2020 Annual Report

The Society of Thoracic Surgeons (STS)-Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) 2020 Annual Report reviews outcomes on 25,551 patients undergoing primary isolated continuous-flow left ventricular assist device (LVAD) implantation between 2010 and 2019. In 2019, 3198 primary LVADs were implanted, which is the highest annual volume in Intermacs history. Compared with the previous era (2010-2014), patients who received an LVAD in the most recent era (2015-2019) were more likely to be African American (26.8% vs 22.9%, P < .0001) and more likely to be bridged to durable LVAD with temporary mechanical support devices (36.8% vs 26.0%, P < .0001). In 2019, 50% of patients were INTERMACS Profile 1 or 2 before durable LVAD, and 73% received an LVAD as destination therapy. Magnetic levitation technology has become the predominant design, accounting for 77% of devices in 2019. The 1- and 2-year survival in the most recent era has improved compared with 2010 to 2014 (82.3% and 73.1% vs 80.5% and 69.1%, respectively; P < .0001). Major bleeding and infection continue to be the leading adverse events. Incident stroke has declined in the current era to 12.7% at 1 year. STS-Intermacs research publications are highlighted, and the new quality initiatives are introduced.

Successful HeartMate 3 LVAD implantation in a patient with active heparin-induced thrombocytopaenia with thrombosis using pre-implantation plasmapheresis and intraoperative continuous prostacyclin

Heparin-induced thrombocytopaenia describes a prothrombotic state with significant rates of thrombus formation. We present a rare case of successful implantation of a HeartMate 3 left ventricular assist device in a patient with active heparin-induced thrombocytopaenia with thrombosis using preoperative plasmapheresis followed by intraoperative prostacyclin administration.

Mediastinal tissue friability-An unreported complication from Mycobacterium chimaera infection post-cardiac surgery

Mycobacterium chimaera can cause disseminated infection following cardiac surgery with cardiopulmonary bypass and contaminated heater-cooler devices. We discuss a 41-year-old man with a disseminated M. chimaera infection following surgery for a type A aortic dissection. His presentation included cachexia and dorsalgia with a work-up revealing vertebral osteomyelitis with an epidural abscess, bone marrow, and pulmonary infiltration, and fluid collection around his aortic graft. He received 1 month of antibiotics before the explantation of infected foreign material, mediastinal debridement, and aortic reconstruction. Complications included septic shock, respiratory and renal failure, mediastinitis, and four distal aortic anastomotic dehiscences from friable tissue and persistent infection.

A Fully Magnetically Levitated Left Ventricular Assist Device - Final Report

BACKGROUND

In two interim analyses of this trial, patients with advanced heart failure who were treated with a fully magnetically levitated centrifugal-flow left ventricular assist device were less likely to have pump thrombosis or nondisabling stroke than were patients treated with a mechanical-bearing axial-flow left ventricular assist device.

METHODS

We randomly assigned patients with advanced heart failure to receive either the centrifugal-flow pump or the axial-flow pump irrespective of the intended goal of use (bridge to transplantation or destination therapy). The composite primary end point was survival at 2 years free of disabling stroke or reoperation to replace or remove a malfunctioning device. The principal secondary end point was pump replacement at 2 years.

RESULTS

This final analysis included 1028 enrolled patients: 516 in the centrifugal-flow pump group and 512 in the axial-flow pump group. In the analysis of the primary end point, 397 patients (76.9%) in the centrifugal-flow pump group, as compared with 332 (64.8%) in the axial-flow pump group, remained alive and free of disabling stroke or reoperation to replace or remove a malfunctioning device at 2 years (relative risk, 0.84; 95% confidence interval [CI], 0.78 to 0.91; P<0.001 for superiority). Pump replacement was less common in the centrifugal-flow pump group than in the axial-flow pump group (12 patients [2.3%] vs. 57 patients [11.3%]; relative risk, 0.21; 95% CI, 0.11 to 0.38; P<0.001). The numbers of events per patient-year for stroke of any severity, major bleeding, and gastrointestinal hemorrhage were lower in the centrifugal-flow pump group than in the axial-flow pump group.

CONCLUSIONS

Among patients with advanced heart failure, a fully magnetically levitated centrifugal-flow left ventricular assist device was associated with less frequent need for pump replacement than an axial-flow device and was superior with respect to survival free of disabling stroke or reoperation to replace or remove a malfunctioning device. (Funded by Abbott; MOMENTUM 3 ClinicalTrials.gov number, NCT02224755.).

Right ventricular beneficial effects of intracoronary SERCA2a gene transfer in an experimental model of heart failure

SERCA2a gene transfer ameliorates heart failure pathologic processes in left ventricular myocardium. We sought to assess the simultaneous molecular changes that occur in the right ventricle. Sprague-Dawley rats underwent aortic banding and were followed by echocardiography for development of heart failure. After a decrease in fractional shortening of 25 % from baseline, intracoronary injection of adenoviral-SERCA2a or adenoviral-beta-galactosidase was performed. Successful gene transfer was confirmed by immunoblotting. Rats were randomly euthanized on post-operative day 7 or 21. Protein analysis including right ventricular levels of SERCA2a, betaARK1, inflammatory mediators (IL-1, IL-6 and TNF-alpha), apoptotic markers (Bax, Bak and Bcl-2) and MAPK (Jnk, p38 and Erk) was performed. Adenoviral-SERCA2a-treated animals showed increased right ventricular expression of SERCA2a compared with controls. Decreased levels of inflammatory markers were also demonstrated in this group. Expression of pro-apoptotic markers was similarly improved. Levels of MAPK were increased compared with the control group. These differences were most significant 7 days after gene transfer, but the majority of these changes persisted at 21 days. These results suggest that attenuation of pathologic mechanisms of calcium cycling, inflammation and apoptosis also occur in the right ventricular myocardium after SERCA2a gene transfer during heart failure. These findings support a therapeutic role for genetic manipulation of this pathway in patients with right ventricular or biventricular failure.

Reverse remodeling is associated with changes in extracellular matrix proteases and tissue inhibitors after mesenchymal stem cell (MSC) treatment of pressure overload hypertrophy

Changes in ventricular extracellular matrix (ECM) composition of pressure overload hypertrophy determine clinical outcomes. The effects of mesenchymal stem cell (MSC) transplantation upon determinants of ECM composition in pressure overload hypertrophy have not been studied. Sprague-Dawley rats underwent aortic banding and were followed by echocardiography. After an absolute decrease in fractional shortening of 25% from baseline, 1 x 10(6) MSC (n = 28) or PBS (n = 20) was randomly injected intracoronarily. LV protein analysis, including matrix metalloproteinases (MMP-2, MMP-3, MMP-6, MMP-9) and tissue inhibitors of metalloproteinases (TIMP-1, TIMP-2, TIMP-3), was performed after sacrifice on postoperative day 7, 14, 21 or 28. Left ventricular levels of MMP-3, MMP-6, MMP-9, TIMP-1 and TIMP-3 were demonstrated to be decreased in the MSC group compared with controls after 28 days. Expression of MMP-2 and TIMP-2 remained relatively stable in both groups. Successful MSCs delivery was confirmed by histological analysis and visualization of labelled MSCs. In this model of pressure overload hypertrophy, intracoronary delivery of MSCs during heart failure was associated with specific changes in determinants of ECM composition. LV reverse remodeling was associated with decreased ventricular levels of MMP-3, MMP-6, MMP-9, TIMP-1 and TIMP-3, which were upregulated in the control group as heart failure progressed. These effects were most significant at 28 days following injection.

Increase in endoplasmic reticulum stress-related proteins and genes in adipose tissue of obese, insulin-resistant individuals

OBJECTIVE

To examine fat biopsy samples from lean insulin-sensitive and obese insulin-resistant nondiabetic individuals for evidence of endoplasmic reticulum (ER) stress.

RESEARCH DESIGN AND METHODS

Subcutaneous fat biopsies were obtained from the upper thighs of six lean and six obese nondiabetic subjects. Fat homogenates were used for proteomic (two-dimensional gel and MALDI-TOF/TOF), Western blot, and RT-PCR analysis.

RESULTS

Proteomic analysis revealed 19 differentially upregulated proteins in fat of obese subjects. Three of these proteins were the ER stress-related unfolded protein response (UPR) proteins calreticulin, protein disulfide-isomerase A3, and glutathione-S-transferase P. Western blotting revealed upregulation of several other UPR stress-related proteins, including calnexin, a membrane-bound chaperone, and phospho c-jun NH(2)-terminal kinase (JNK)-1, a downstream effector protein of ER stress. RT-PCR analysis revealed upregulation of the spliced form of X-box binding protein-1s, a potent transcription factor and part of the proximal ER stress sensor inositol-requiring enzyme-1 pathway.

CONCLUSIONS

These findings represent the first demonstration of UPR activation in subcutaneous adipose tissue of obese human subjects. As JNK can inhibit insulin action and activate proinflammatory pathways, ER stress activation of JNK may be a link between obesity, insulin resistance, and inflammation.

Right ventricular beneficial effects of beta adrenergic receptor kinase inhibitor (betaARKct) gene transfer in a rat model of severe pressure overload

Heart failure is associated with abnormalities in betaAR cascade regulation, calcium cycling, expression of inflammatory mediators and apoptosis. Adenoviral mediated gene transfer of betaARKct has beneficial indirect effects on these pathologic processes upon the left ventricular myocardium. The concomitant biochemical changes that occur in the right ventricle have not been well characterized. Sprague-Dawley rats underwent aortic banding and were followed by echocardiography. After a decrease in fractional shortening of 25% from baseline, intracoronary injection of adenoviral-betaARKct (n=14) or adenoviral-beta-galactosidase (control, n=13) was performed. Rats were randomly euthanized on post-operative day 7, 14 or 21. Protein analysis including RV myocardial levels of betaARKct, betaARK1, SERCA(2a), inflammatory tissue mediators (IL-1, IL-6 and TNF-alpha), apoptotic markers (bax and bak), and MAP kinases (jnk, p38 and erk) was performed. ANOVA was employed for group comparison. Adenoviral-betaARKct treated animals showed increased expression of betaARKct and decreased levels of betaARK1 compared with controls. This treatment group also demonstrated normalization of SERCA(2a) expression and decreased levels of the inflammatory markers IL-1, IL-6 and TNF-alpha. The pro-apoptotic markers bax and bak were similarly improved. Ventricular levels of the MAP kinase jnk were increased. Differences were most significant 7 days after gene transfer, but the majority of these changes persisted at 21 days. These results suggest that attenuation of the pathologic mechanisms of beta adrenergic receptor desensitization, SERCA(2a) expression, inflammation and apoptosis, not only occur in the left ventricle but also in the right ventricular myocardium after intracoronary gene transfer of betaARKct during heart failure.

Thoracic outlet syndrome: evaluation of the subclavian vessels by color duplex sonography

Changes in flow in the subclavian artery and vein resulting from the use of a hyperabduction maneuver during Doppler sonography in 20 volunteers were compared with retrospective findings in 16 patients clinically suspected of having thoracic outlet syndrome. Significant compression of the subclavian artery showed in the Doppler waveform as at least a doubling of peak systolic velocity or complete cessation of flow with hyperabduction; significant compression of the subclavian vein was diagnosed by complete cessation of blood flow or loss of atrial and respiratory dynamics in the waveform of the subclavian vein with hyperabduction. In volunteers, asymptomatic compression of the subclavian vein with arm abduction was seen in two (10%) and asymptomatic compression of the subclavian artery was seen in four (20%). Of the 16 patients, thrombosis of the subclavian vein was found in seven, compression of the subclavian vein with hyperabduction was found in six, and diagnoses other than thoracic outlet syndrome were established as the cause of pain in three. When duplex sonography was compared with venography, which was performed in 10 patients, one false-negative case was found because a subclavian vein thrombus had not been detected. The subclavian artery was examined in five of the six patients with positional compression of the subclavian vein; compression of the subclavian artery was found in three. The clinical significance of compression of the subclavian artery cannot be determined from our data because of the small number of patients involved. When the sonographic criteria of subclavian vein clot or compression resulting in a complete loss of normal venous phasicity with arm abduction and the clinical criterion of subsequent improvement in symptoms after curative surgery are used, color Doppler sonography is 92% sensitive and 95% specific for the diagnosis of thoracic outlet syndrome. This preliminary study shows that Doppler sonography has potential in the evaluation of thoracic outlet syndrome.

Prosthesis for correction of single ventricle

A prosthetic right ventricular conduit that may be applicable in repair of the single ventricle anomaly is reported. The final conduit evolved from a series of animal experiments, which are described.