Amber L. Melvin

Cannulation‐Related Complications on Veno‐Arterial Extracorporeal Membrane Oxygenation: Prevalence and Effect on Mortality

Cannulation-related complications are a known source of morbidity in patients supported on veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Despite its prevalence, little is known regarding the outcomes of patients who suffer such complications. This is a single institution review of cannulation-related complications and its effect on mortality in patients supported on VA-ECMO from January 2010-2015 using three cannulation strategies: axillary, femoral, and central. Complications were defined as advanced if they required major interventions (fasciotomy, amputation, site conversion). Patients were divided into two groups (complication present vs. not present) and Kaplan-Meier analysis was performed to determine any differences in their survival distributions. There were 103 patients supported on VA-ECMO: 41 (40%), 36 (35%), and 26 (25%) were cannulated via axillary, femoral, and central access, respectively. Cannulation-related complications occurred in 33 (32%) patients and this did not differ significantly between either axillary (34%), femoral (36%), or central (23%) strategies (P = 0.52). The most common complications encountered were hemorrhage and limb ischemia in 19 (18%) and 11 (11%) patients. Hemorrhagic complications did not differ between groups (P = 0.37), while limb ischemia and hyperperfusion were significantly associated with femoral and axillary cannulation, at a rate of 25% (P < 0.01) and 15% (P = 0.01), respectively. There was no difference in the incidence of advanced complications between cannulation groups: axillary (12%) vs. femoral (14%) vs. central (8%; P = 0.75). In addition, no increase in mortality was noted in patients who developed a cannulation-related complication by Kaplan-Meier estimates (P = 0.37). Cannulation-related complications affect a significant proportion of patients supported on VA-ECMO but do not differ in incidence between different cannulation strategies and do not affect patient mortality. Improved efforts at preventing these complications need to be developed to avoid the additional morbidity in an already critical patient population.

Late erosion of Amplatzer septal occluder device resulting in cardiac tamponade

Transcatheter device closure of atrial septal defects (ASDs) is a minimally invasive technique that offers an alternative to conventional surgical repair. There are risks imposed by this technique; however, they compare favourably with risks of surgical closure. Here, we present a case of a 59-year old male with late erosion of an Amplatzer septal occluder device resulting in cardiac tamponade 5 years after device placement. To the best of our knowledge, cardiac tamponade this late after device placement has not yet been reported. Septal occlusion device erosion remains a major issue among the risks imposed by device closure of an ASD. More data are needed to better understand its true causes and possible solutions.

Anticoagulation Reversal Strategies for Left Ventricular Assist Device Patients Presenting with Acute Intracranial Hemorrhage

The safety of alternative vitamin K antagonist (VKA) reversal strategies in patients with left ventricular assist devices (LVAD’s) who present with intracranial hemorrhage (ICH) are not well known. A review of LVAD patients with ICH from May 2008 to 2015 was conducted, comparing the safety and efficacy of 4-factor prothrombin complex concentrate-assisted VKA reversal (4F-PCC group, n = 10) to reversal with traditional agents alone (no-PCC group, n = 10). An analysis of a no-reversal strategy in selected patients (n = 11) with ICH was additionally performed. Thirty-one cases of ICH on LVAD support were reviewed. The rate of post reversal thromboembolic events was not significantly different between 4F-PCC and no-PCC patients (0% vs. 10%, p = 1.0); however, the time to VKA reversal was shorter (474 vs. 945 minutes, p = 0.02) and fresh frozen plasma (FFP) requirements lower (1.9 vs. 3.6 units, p = 0.05) in 4F-PCC patients, with no difference in mortality between groups (p = 1.0). Eleven patients (mean ICH volume: 0.4 cm3) were successfully managed without active VKA reversal, with no increased hemorrhage noted on neuroimaging. These results suggest that 4F-PCC-assisted reversal in LVAD patients is safe and may improve the efficacy of VKA reversal. Our findings also indicate that carefully selected patients with small ICH volumes may be safely managed by discontinuing anticoagulation and allowing the international normalized ratio (INR) to normalize physiologically.

Early and late outcomes with prolonged open chest management after cardiac surgery

Objectives: Open chest management (OCM) is an important intervention for patients who are unable to undergo sternal closure after cardiac surgery. This study reviews the factors associated with a prolonged need for this intervention and investigates its association with early and late mortality. Methods: Patients undergoing OCM from January 2009 to December 2014 were reviewed. Differences in the median duration of OCM when a perioperative variable was present versus its absence were determined and variables significant at P ≤ .1 were analyzed using Poisson regression for factors associated with prolonged OCM. Multivariable logistic regression and Cox proportional hazards models were developed to investigate perioperative factors that were associated with early and late mortality. Results: A total of 201 patients (5%) required OCM and the overall median duration of this intervention was 3 days. The use a temporary assist device (median, 7 vs 2 days; P < .001), pneumonias (median, 11 vs 3 days; P < .001), sternal re‐explorations (median, 6 vs 2 days; P < .001), and renal failure (median, 6 vs 3 days; P = .02) were among the factors that were highly associated with prolonged OCM using Poisson regression. Thirty‐day mortalities occurred in 32 patients (16%) and were significantly associated with emergency surgery (P = .03), sternal re‐explorations (P = .001), and OCM duration (median, 6 vs 3 days; P = .02). On multivariable logistic regression and Cox analysis, delaying sternal closure by 1‐day increments increased the risk of early and late mortality by 11% (P = .01), and 9% (P < .001), respectively. Conclusions: Prolonged OCM was associated with increasing perioperative morbidity and a higher risk of early and late mortality.

Single‐Center Experience With HeartMate II Left Ventricular Assist Device Explantation

In patients with continuous flow left ventricular assist devices (CF-LVADs) myocardial recovery is uncommon. Given the heterogeneity of the population implanted and low incidence of recovery, the discovery of native left ventricular (LV) recovery and criteria for explantation of CF-LVAD system is not clearly determined. We sought to analyze the characteristics of the patients who underwent CF-LVAD explantation at our institution. Prospectively collected data on patients supported with CF-LVADs were reviewed retrospectively. Patients who underwent CF-LVAD explants were identified and their characteristics were analyzed with a focus on patient presentation and determinants of explantability. From November 2006 to June 2014, 223 patients (181 male, 42 female) underwent implantation of HeartMate II LVAD. Seven female (16.7%) and one male (0.6%) patients were explanted (P < 0.001). Mean age was 43 ± 9 years and etiology for cardiomyopathy was ischemic in three (37.5%) patients, nonischemic in four (50%) patients, and mixed in the one (12.5%) male patient of the cohort. Five (62.5%) patients presented acutely with significant hemolysis, and were found to have LV improvement as well as reduced, absent, or reversed diastolic flow velocities on echocardiography. Overall, mean lactate dehydrogenase level before explantation was 1709 ± 1168 U/L compared to the mean baseline level of 601 ± 316 U/L (P = 0.048). Mean LV ejection fraction (LVEF) improved from 17 ± 7% preimplant to 56 ± 11% pre-explantation (P < 0.001). Median number of days on CF-LVAD support was 870 (interquartile range, 209-975) while mean duration of follow-up after the CF-LVAD explantation was 276 ± 240 days. Mean LVEF dropped from 46 ± 19% postexplantation to 34 ± 10% during the most recent follow-up (P = 0.015). At our institution, patients who underwent LVAD explants were predominantly women with nonischemic cardiomyopathy. Clinical evidence of hemolysis and echocardiographic evidence of reduced or absent diastolic flow velocities were common findings in these patients. Over time, patients native LV function declined in the absence of LVAD (after LVAD explantation). Significant challenges remain in predicting LV recovery and identifying those individuals who have recovered myocardial function significant enough to be explanted.

Video assisted right mini-thoracotomy for aortic valve replacement

Aortic root replacement is typically performed through a median sternotomy. The right anterior mini-thoracotomy approach has been shown to decrease hospital length of stay in aortic valve surgery when compared to sternotomy. This approach is rare in ascending aortic surgery due to technical challenges which include exposure and annular suture placement. Automated suturing technology is now available to facilitate the placement of annular sutures. The use of a camera greatly enhances visualization of the aortic root. A right anterior mini-thoracotomy is performed via a 5 cm incision in the right second intercostal space with a camera port placed lateral to the incision. Peripheral arterial and venous cannulation are performed. The aortic cross clamp is placed through a 5 mm incision in the third interspace anterior to mid axillary line. Histidine tryptophan ketoglutarate (HTK) cardioplegia is administered and deep hypothermic circulatory arrest is achieved followed by completion of the distal anastomosis with a 4-0 polypropylene running suture. After aortic leaflet removal, annular and prosthetic sutures are placed with shafted instruments or with automated suturing technology. Coronary button suturing and graft-to-graft anastomoses are performed with shafted instruments. Aortic root procedures can be performed safely through a right anterior mini-thoracotomy. The use of a camera and automated suturing technology may further facilitate this procedure, enabling more surgeons to offer this less invasive approach to patients.

Novel Automated Suturing Technology for Minimally Invasive Aortic Valve Replacements

PURPOSE Annular suture placement during minimally invasive right anterior thoracotomy aortic valve replacements (MI-AVR) can be challenging. We present the early clinical experience with novel automated suturing technology that may reduce the technical difficulty of this operation. DESCRIPTION The technology presented involves an automated articulating suturing device that simultaneously drives dual-curved needles through the aortic annulus to place a pledgeted horizontal mattress suture remotely; a second device with 2 straight needles places suture through the sewing cuff of a prosthetic heart valve. EVALUATION Automated annular suturing was used in five MI-AVR procedures, which were successfully completed, with no paravalvular leaks detected and a mean aortic valve gradient of 6.4 mm Hg postprocedure. Mean aortic cross-clamp and cardiopulmonary bypass times were 100 and 134 minutes, respectively. All 5 patients were successfully discharged home, with a mean intensive care unit and total length of stay of 2 and 7 days, respectively. CONCLUSIONS Automated suturing during MI-AVRs is feasible and may reduce the technical challenge of this operation. Further research is necessary to determine its effect on patient outcomes.