Perioperative Extracorporeal Cardiopulmonary Resuscitation in Adult Patients: A Review for the Perioperative Physician

The use of extracorporeal cardiopulmonary resuscitation for refractory cardiac arrest has grown rapidly over the previous decade. Considerations for the implementation and management of extracorporeal cardiopulmonary resuscitation are presented for the perioperative physician.

Insurance-Based Disparities in Outcomes and ECMO Utilization for Hospitalized COVID-19 Patients

BACKGROUND

The objective of this study was to examine insurance-based disparities in mortality, non-home discharges, and ECMO utilization in patients hospitalized with COVID-19.

METHODS

Using a national database of U.S. academic medical centers and their affiliated hospitals, the risk-adjusted association between mortality, non-home discharge, and ECMO utilization and (1) the type of insurance coverage (private insurance, Medicare, dual enrollment in Medicare and Medicaid, and no insurance) and (2) the weekly hospital COVID-19 burden (0-5.0%; 5.1-10%, 10.1-20%, 20.1-30%, 30.1%-) was evaluated. Modelling was expanded to include an interaction between payer status and the weekly hospital COVID-19 burden to examine whether the lack of private insurance was associated with increases in disparities as the COVID-19 burden increased.

RESULTS

Among 760,846 patients hospitalized with COVID-19, 214,992 had private insurance, 318,624 had Medicare, 96,192 were dually enrolled in Medicare and Medicaid, 107,548 had Medicaid, and 23,560 had no insurance. Overall, 76,250 died, 211,702 had non-home discharges, 75,703 were mechanically ventilated, and 2,642 underwent ECMO. The adjusted odds of death were higher in patients with Medicare (aOR 1.28; [95% CI: 1.21, 1.35]; P<0.0005), dually enrolled (aOR, 1.39; [1.30, 1.50]; P<0.0005), Medicaid (aOR, 1.28; [1.20, 1.36]; P<0.0005), and no insurance (aOR, 1.43; [1.26, 1.62]; P<0.0005) compared to patients with private insurance. Patients with Medicare (aOR, 0.47; [CI: 0.39, 0.58]; P <0.0005), dually enrolled (aOR, 0.32; [0.24, 0.43]; P<0.0005), Medicaid (aOR, 0.70; [ 0.62, 0.79]; P<0.0005), and no insurance (aOR, 0.40; [0.29, 0.56]; P<0.001] were less likely to be placed on ECMO than patients with private insurance. Mortality, non-home discharges, and ECMO utilization did not change significantly more in patients with private insurance compared to patients without private insurance as the COVID-19 burden increased.

CONCLUSION

Among patients with COVID-19, insurance-based disparities in mortality, non-home discharges, and ECMO utilization were substantial, but these disparities did not increase as the hospital COVID-19 burden increased.

The Society of Thoracic Surgeons Intermacs 2023 Annual Report: Focus on Magnetically Levitated Devices

The 14th Annual Report from The Society of Thoracic Surgeons (STS) Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) describes outcomes of 27,493 patients with a continuous-flow left ventricular assist device (LVAD) from the past decade (2013-2022). In 2022, 2517 primary LVADs were implanted, of which 2512 (99.8%) were fully magnetically levitated (Mag-Lev) devices. This shift to nearly exclusive use of a Mag-Lev device led us to examine its outcomes compared with contemporary (2018-2022) and historical (2013-2017) non-Mag-Lev cohorts. Patients supported by a Mag-Lev device (n = 10,920) had a higher 1- and 5-year survival of 86% (vs 79% and 81%, P < .0001) and 64% (vs 44% and 44%, P < .0001), respectively, than those receiving non-Mag-Lev devices during the contemporary and historical eras. Over 5 years, freedom from gastrointestinal bleeding (72% vs 60%, P < .0001), stroke (87% vs 67%, P < .0001), and device malfunction/pump thrombus (83% vs 54%, P < .0001), but not device-related infection (61% vs 64%, P = .93), was higher with Mag-Lev devices compared with non-Mag-Lev support during the contemporary era. In this large primacy cohort of real-world patients with advanced heart failure, this report underscores marked improvements in short- and intermediate-term survival and reduction of adverse events with a contemporary Mag-Lev LVAD.

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.

Less Invasive Left Ventricular Assist Device Implantation Is Safe and Feasible in Patients With Smaller Body Surface Area

OBJECTIVE

Smaller body surface area (BSA) frequently precludes patients from left ventricular assist device (LVAD) therapy. We sought to investigate the clinical outcomes in patients with small BSA undergoing less invasive LVAD implantation.

METHODS

We conducted a retrospective review of 216 patients implanted with HeartMate 3 LVAD (Abbott, Chicago, IL) via less invasive surgery at our institution. Patients were dichotomized based on their preimplant BSA for comparison between small BSA (≤1.8 m2) and normal/large BSA (>1.8 m2). We analyzed patient perioperative characteristics and outcomes.

RESULTS

In our study, small BSA was found in 32 patients (14.8%), while 184 patients (85.2%) had normal/large BSA. Women were more prevalent in the small BSA group (50.0% vs 13.0%, P < 0.001). Preoperative and intraoperative data showed comparable results. Major complications and hospital length of stay did not differ by BSA group. Patients with smaller BSA had significantly decreased pump parameters at discharge, including LVAD flow (4.11 ± 0.49 vs 4.60 ± 0.54 L/min, P < 0.001) and pump speed (5,200 vs 5,400 rpm, P < 0.001). Survival to discharge and within 6 months after implantation were similar between the groups.

CONCLUSIONS

Our study results suggest that less invasive HeartMate 3 implantation can be safely performed and demonstrates equivalent outcomes in patients with smaller body habitus. Randomized trials are required to confirm our data.

Left atrial appendage exclusion with less invasive left ventricular assist device implantation

OBJECTIVES

The objective of this single-center, pilot, prospective, and historical control study is to evaluate safety and feasibility outcomes associated with left atrial appendage exclusion (LAAE) concomitant with left ventricular assist device (LVAD) implantation via less invasive surgery (LIS) as a stroke prevention strategy.

METHODS

A predefined number of 30 eligible subjects scheduled for LIS LVAD with LAAE were enrolled in the prospective arm between January 2020 and February 2021. Eligible retrospective LIS LVAD patients without LAAE were propensity-matched in a 1:1 ratio with the prospective arm subjects. The primary study objectives were to evaluate the safety, feasibility, and efficacy of the LAAE concomitant with LIS LVAD.

RESULTS

Preoperative characteristics of patients in the Non-LAAE and LAAE groups were similar. LAAE was successfully excluded in all prospective patients (100%). Primary safety endpoints of chest tube output within the first 24 postoperative hours, Reoperation for bleeding within 48 h, and index hospitalization mortality demonstrated comparable safety of LAAE versus Non-LAAE with LIS LVAD. Cox proportional hazard regression demonstrated that LAAE with LIS LVAD was associated with 37% and 49% reduction in the risk of stroke and disabling stroke, respectively (p > .05).

CONCLUSION

Results from our pilot study demonstrated the safety and feasibility of LAAE concomitant with LIS LVAD as a stroke prevention strategy. This is the first prospective study describing LAAE performed concomitantly to less invasive LVAD implantation. The efficacy of LAAE in long-term stroke prevention needs to be confirmed in future prospective randomized clinical trials.

Video assisted right mini-thoracotomy for aortic root 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.

Treatment of advanced or recurrent cervical cancer with Cisplatin or Cisplatin containing regimens: a cost effective analysis

Background: Trials have demonstrated improvements in survival with adding paclitaxel (P) or topotecan (T) to cisplatin (C) for the treatment of advanced cervical cancer. We sought to evaluate the cost effectiveness of these regimens.

Methods: A decision model was developed based on Gynecologic Oncology Group (GOG) protocols 169 and 179. Arm 1 is 6 cycles of cisplatin. Arm 2 is 6 cycles of CP while arm 3 is 6 cycles of CT. Parameters include overall survival (OS), cost and complications. Sensitivity analyses were performed.

Results: The incremental cost-effectiveness ratio (ICER) for C versus CP is $13,654/quality-adjusted life-year (QALY) gained. For CT compared to C, the ICER is $152,327/QALY. When compared simultaneously, CT is dominated. At a willingness to pay (WTP) threshold of $50,000/QALY, C is the preferred option but CP is acceptable. Sensitivity analyses suggest that CT would become the preferred option if it was to improve OS to 24 months (compared to 9.4 months).

Conclusions: In this model, CP is an acceptable alternative to cisplatin for the treatment of these patients with an increase in cost of only $13,654/QALY. The addition of topotecan did not increase survival enough to justify the increased cost.

Effect of bronchopulmonary lavage on lung retention and clearance of particulate material in hamsters

Hamsters were exposed to an aerosol of fused aluminosilicate particles (FAP) labeled with 57Co. Three groups of animals were given bronchopulmonary lavage, beginning at either 1 week, 1 month, or 6 months after exposure. Each treated group was lavaged eight times over a period of 25 days. Each lavage involved 10 saline washes of the lungs. For each group, about 60-70% of the body content of 57Co at the start of lavage treatment was removed; nearly half of this was recovered in the first two lavages. A positive correlation was demonstrated between the macrophage content and 57Co activity of the washings. The subsequent fractional clearance rate of 57Co from lavaged animals was not significantly different from that in a group of untreated control animals.

Effect of activity on supraventricular tachyarrhythmias after coronary artery bypass surgery

The purpose of this study was to evaluate patient activities, professional staff activities, backrest position, and diurnal variations as factors that may contribute to the onset of supraventricular tachyarrhythmias (SVT) after coronary artery bypass surgery (CABG). The activities surrounding the recognition of first-onset SVT, as well as preoperative and postoperative data and patient characteristics were examined in 249 patients having CABG. One hundred seventy-three patients qualified for the study; 28% of these patients (n = 49) had SVT. No statistical difference was found between the subjects with SVT and those without SVT when sex, cross-clamp time, creatine kinase peak, hemoglobin and hematocrit levels, and number of bypasses were examined. Patients who had SVT were older than those who did not: 64.8 years for the SVT group versus 60.7 years for the non-SVT group (p less than 0.01). SVT was rare in the first 24 hours after surgery, whereas 60% of the cases occurred during the next 48 hours, without significant diurnal variation: mean time of onset was 11:50 AM. No particular activity of the patient or nurse influenced the onset of SVT during the postoperative period in this group.

Vagally mediated gastric motor and emetic reflexes evoked by stimulation of the antral mucosa in anaesthetized ferrets

1. In the urethane-anaesthetized ferret chemical (NaCl, NaOH or HCl) or mechanical (stroking) stimulation of the gastric antral mucosa evoked a decrease in corpus pressure and inhibition of contractions in the presence of guanethidine, adrenalectomy and sectioned greater splanchnic nerves. 2. The fall in corpus pressure was present following administration of atropine but was abolished by vagotomy. 3. Preliminary evidence, using 100 mM-NaOH as the stimulus, is presented that the effects on corpus motility are due to simultaneous activation of the vagal efferents supplying the intramural non-adrenergic non-cholinergic inhibitory neurones and inhibition of those supplying the intramural cholinergic neurones. 4. The possible roles of this antro-corpus vago-vagal reflex in the regulation of gastric emptying and in the prodromal phase of vomiting are discussed.

Selective antagonism of platelet-activating factor (PAF)-induced aggregation and secretion in washed rabbit platelets by CV-3988, L-652731, triazolam and alprazolam

Platelet-activating factor (1-O-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine or AGEPC) is a potent phospholipid mediator elaborated by a variety of mammalian cells. CV-3988 (a unique structural analog of AGEPC), L-652731 (a lignan derivative of a natural product) and two triazolobenzodiazepines (triazolam and alprazolam) were evaluated for their ability to selectively antagonize aggregation and secretion responses in washed, [3H]serotonin-labeled rabbit platelets stimulated with graded doses of AGEPC. When 0.2 nM AGEPC was used as the stimulus, the concentration of antagonist needed for 50% inhibition (IC50) of secretion was obtained at 0.05 uM, 0.15 uM, 0.6 uM and 2.5 uM, for L-652732, CV-3988, triazolam and alprazolam, respectively. The corresponding IC50 values for aggregation were obtained at 0.2 uM, 0.1 uM, 1.5 uM and 6.5 uM, respectively. The inhibitory effects could be overcome by increasing the amount of AGEPC used to stimulate the platelets. Of the four compounds tested, L-652731 was the most potent antagonist of AGEPC-induced activation of washed rabbit platelets.

Injection of baclofen into the ventromedial hypothalamus stimulates gastric motility in the rat

Injection of 2 micrograms (+/-)-baclofen into the ventromedial hypothalamus (VMH) of urethane-anaesthetized rats resulted in an increase in gastric tone and amplitude of contractions. This effect was curtailed by administration of atropine methyl nitrate (20 mg/kg i.p.) or bilateral cervical vagotomy. These results provide evidence for a hypothalamic modulation of gastric motility by the vagus. Baclofen, possibly acting on receptors insensitive to gamma-aminobutyric acid (GABA), may be mimicking a vagal activation system, located within the ventro-medial hypothalamus.

Modulation of the vagal drive to the intramural cholinergic and non-cholinergic neurones in the ferret stomach by baclofen

1. In the urethane-anaesthetized ferret vagotomy (cervical and abdominal) and hexamethonium both produced an increase in gastric corpus pressure after treatment with atropine and guanethidine, section of the greater splanchnic nerves and adrenalectomy. 2. The pressure increase was due to an interruption of a tonic vagal drive to the intramural non-adrenergic, non-cholinergic inhibitory neurones. 3. The GABAB receptor agonist baclofen (8 mg/kg s.c.) produced an increase in gastric pressure and enhanced the amplitude of the rhythmic contractions. Baclofen was without effect in vagotomized animals. 4. In the presence of atropine, guanethidine, adrenalectomy and section of the greater splanchnic nerves, baclofen produced only a slight enhancement of rhythmic contractions but the large increase in gastric pressure was still present. Under the above conditions the effects of baclofen on the whole stomach were virtually identical to those observed in the corpus region alone. 5. Baclofen was without effect on the magnitude of the corpus relaxation produced by the submaximal vagal efferent stimulation in the presence of atropine. 6. These results demonstrate that the GABAB agonist baclofen, probably acting at a central site, enhanced rhythmic gastric activity by increasing the vagal drive to the intramural cholinergic neurones. Simultaneously gastric pressure was increased primarily by a reduction in the tonic vagal drive to the intramural non-adrenergic, non-cholinergic inhibitory neurones in the corpus region. The results of both the baclofen and vagotomy studies further demonstrate the importance of the vagal innervation of the non-adrenergic, non-cholinergic inhibitory neurones in the regulation of gastric pressure.

An extract of rat submandibular glands activates platelets and enhances cutaneous vascular permeability in rats and guinea pigs

Washed, [3H]serotonin-labeled platelets from rats and guinea pigs were stimulated in vitro with a novel protein extracted from rat submandibular salivary glands (RS-PAP) and with the phospholipid platelet- activating factor 1-0-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine (AGEPC). Rat platelets, which are refractory to AGEPC stimulation, underwent shape-change, aggregation and secretion of [3H]serotonin in response to graded doses of RS-PAP and AGEPC. Intradermal injections of histamine, RS-PAP and AGEPC caused a dose-related increase in local microvascular permeability in rats, as measured by the extravasation of plasma containing Evans blue dye. Similarly, histamine, RS-PAP and AGEPC increased cutaneous vascular permeability when injected intradermally in guinea pigs. The vascular permeability induced by histamine and RS-PAP, but not by AGEPC, was partially inhibited by pretreatment with an antihistamine (diphenhydramine HCl). Pretreatment of guinea pigs with captopril, an inhibitor of angiotensin-converting enzyme (ACE), partially inhibited cutaneous responses to subsequent intradermal injections of histamine, RS-PAP and AGEPC. Regardless of pretreatment with diphenhydramine or captopril, skin test sites injected with large amounts of RS-PAP became hemorrhagic within minutes and necrotic within 12 hours.

Systemic baclofen stimulates gastric motility and secretion via a central action in the rat

Intravenous (0.5 mg kg-1) or subcutaneous (2-16 mg kg-1) administration of the gamma-aminobutyric acid (GABA) analogue baclofen resulted in a stimulation of gastric motility and secretion in the rat, anaesthetized with urethane. The motility response to subcutaneous injection was dose-related. This effect was abolished by vagotomy or atropine. There was no response to baclofen in decerebrate animals. These results indicate that systemic baclofen, probably acting at a site rostral to the brainstem, stimulates gastric motility and acid secretion by a vagally-dependent mechanism.