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.

Blood flow kinetic energy is a novel marker for right ventricular global systolic function in patients with left ventricular assist device therapy

Objectives

Right ventricular (RV) failure remains a major concern in heart failure (HF) patients undergoing left ventricular assist device (LVAD) implantation. We aimed to measure the kinetic energy of blood in the RV outflow tract (KE-RVOT) - a new marker of RV global systolic function. We also aimed to assess the relationship of KE-RVOT to other echocardiographic parameters in all subjects and assess the relationship of KE-RVOT to hemodynamic parameters of RV performance in HF patients.

Methods

Fifty-one subjects were prospectively enrolled into 4 groups (healthy controls, NYHA Class II, NYHA Class IV, LVAD patients) as follows: 11 healthy controls, 32 HF patients (8 NYHA Class II and 24 Class IV), and 8 patients with preexisting LVADs. The 24 Class IV HF patients included 21 pre-LVAD and 3 pre-transplant patients. Echocardiographic parameters of RV function (TAPSE, St', Et', IVA, MPI) and RV outflow color-Doppler images were recorded in all patients. Invasive hemodynamic parameters of RV function were collected in all Class IV HF patients. KE-RVOT was derived from color-Doppler imaging using a vector flow mapping proprietary software. Kruskal-Wallis test was performed for comparison of KE-RVOT in each group. Correlation between KE-RVOT and echocardiographic/hemodynamic parameters was assessed by linear regression analysis. Receiver operating characteristic curves for the ability of KE-RVOT to predict early phase RV failure were generated.

Results

KE-RVOT (median ± IQR) was higher in healthy controls (55.10 [39.70 to 76.43] mW/m) than in the Class II HF group (22.23 [15.41 to 35.58] mW/m, p < 0.005). KE-RVOT was further reduced in the Class IV HF group (9.02 [5.33 to 11.94] mW/m, p < 0.05). KE-RVOT was lower in the LVAD group (25.03 [9.88 to 38.98] mW/m) than the healthy controls group (p < 0.005). KE-RVOT had significant correlation with all echocardiographic parameters and no correlation with invasive hemodynamic parameters. RV failure occurred in 12 patients who underwent LVAD implantation in the Class IV HF group (1 patient was not eligible due to death immediately after the LVAD implantation). KE-RVOT cut-off value for prediction of RV failure was 9.15 mW/m (sensitivity: 0.67, specificity: 0.75, AUC: 0.66).

Conclusions

KE-RVOT, a novel noninvasive measure of RV function, strongly correlates with well-established echocardiographic markers of RV performance. KE-RVOT is the energy generated by RV wall contraction. Therefore, KE-RVOT may reflect global RV function. The utility of KE-RVOT in prediction of RV failure post LVAD implantation requires further study.

Racial and Ethnic Disparities in Access to Minimally Invasive Mitral Valve Surgery

IMPORTANCE

Whether people from racial and ethnic minority groups experience disparities in access to minimally invasive mitral valve surgery (MIMVS) is not known.

OBJECTIVE

To investigate racial and ethnic disparities in the utilization of MIMVS.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used data from the Society of Thoracic Surgeons Database for patients who underwent mitral valve surgery between 2014 and 2019. Statistical analysis was performed from January 24 to August 11, 2022.

EXPOSURES

Patients were categorized as non-Hispanic White, non-Hispanic Black, and Hispanic individuals.

MAIN OUTCOMES AND MEASURES

The association between MIMVS (vs full sternotomy) and race and ethnicity were evaluated using logistic regression.

RESULTS

Among the 103 753 patients undergoing mitral valve surgery (mean [SD] age, 62 [13] years; 47 886 female individuals [46.2%]), 10 404 (10.0%) were non-Hispanic Black individuals, 89 013 (85.8%) were non-Hispanic White individuals, and 4336 (4.2%) were Hispanic individuals. Non-Hispanic Black individuals were more likely to have Medicaid insurance (odds ratio [OR], 2.21; 95% CI, 1.64-2.98; P < .001) and to receive care from a low-volume surgeon (OR, 4.45; 95% CI, 4.01-4.93; P < .001) compared with non-Hispanic White individuals. Non-Hispanic Black individuals were less likely to undergo MIMVS (OR, 0.65; 95% CI, 0.58-0.73; P < .001), whereas Hispanic individuals were not less likely to undergo MIMVS compared with non-Hispanic White individuals (OR, 1.08; 95% CI, 0.67-1.75; P = .74). Patients with commercial insurance had 2.35-fold higher odds of undergoing MIMVS (OR, 2.35; 95% CI, 2.06-2.68; P < .001) than those with Medicaid insurance. Patients operated by very-high volume surgeons (300 or more cases) had 20.7-fold higher odds (OR, 20.70; 95% CI, 12.7-33.9; P < .001) of undergoing MIMVS compared with patients treated by low-volume surgeons (less than 20 cases). After adjusting for patient risk, non-Hispanic Black individuals were still less likely to undergo MIMVS (adjusted OR [aOR], 0.88; 95% CI, 0.78-0.99; P = .04) and were more likely to die or experience a major complication (aOR, 1.25; 95% CI, 1.16-1.35; P < .001) compared with non-Hispanic White individuals.

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, non-Hispanic Black patients were less likely to undergo MIMVS and more likely to die or experience a major complication than non-Hispanic White patients. These findings suggest that efforts to reduce inequity in cardiovascular medicine may need to include increasing access to private insurance and high-volume surgeons.

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.

Impact of surgical approach for left ventricular assist device implantation on postoperative invasive hemodynamics and right ventricular failure

BACKGROUND

Right ventricular failure (RVF) remains one of the major causes of morbidity and mortality after left ventricular assist device (LVAD) implantation. We sought to compare immediate postoperative invasive hemodynamics and the risk of RVF following two different surgical approaches: less invasive surgery (LIS) versus full sternotomy (FS).

METHODS

The study population comprised all 231 patients who underwent implantation of a HeartMate 3 (Abbott) LVAD at our institution from 2015 to 2020, utilizing an LIS (n = 161; 70%) versus FS (n = 70; 30%) surgical approach. Outcomes included postoperative invasive hemodynamic parameters, vasoactive-inotropic score (VIS), RVF during index hospitalization, and 6-month mortality.

RESULTS

Baseline clinical characteristics of the two groups were similar. Multivariate analysis showed that LIS, compared with FS, was associated with the improved cardiac index (CI) at the sixth postoperative hour (p = .036) and similar CI at 24 h, maintained by lower VIS at both timepoints (p = .002). The LIS versus FS approach was also associated with a three-fold lower incidence of in-hospital severe RVF (8.7% vs. 28.6%, p < .001) and need for RVAD support (5.0% vs. 17.1%, p = .003), and with 68% reduction in the risk of 6-month mortality after LVAD implantation (Hazard ratio, 0.32; CI, 0.13-0.78; p = .012).

CONCLUSION

Our findings suggest that LIS, compared with FS, is associated with a more favorable hemodynamic profile, as indicated by similar hemodynamic parameters maintained by lower vasoactive-inotropic support during the acute postoperative period. These findings were followed by a reduction in the risk of severe RVF and 6-month mortality in the LIS group.

Association Between the COVID-19 Pandemic and Disparities in Access to Major Surgery in the US

IMPORTANCE

Racial minority groups account for 70% of excess deaths not related to COVID-19. Understanding the association of the Centers for Medicare & Medicaid Services' (CMS's) moratorium delaying nonessential operations with racial disparities will help shape future pandemic responses.

OBJECTIVE

To evaluate the association of the CMS's moratorium on elective operations during the first wave of the COVID-19 pandemic among Black individuals, Asian individuals, and individuals of other races compared with White individuals.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study assessed a 719-hospital retrospective cohort of 3 470 905 adult inpatient hospitalizations for major surgery between January 1, 2018, and October 31, 2020.

EXPOSURE

The first wave of COVID-19 infections between March 1, 2020, and May 31, 2020.

MAIN OUTCOMES AND MEASURES

The main outcome was the association between changes in monthly elective surgical case volumes and the first wave of COVID-19 infections as a function of patient race, evaluated using negative binomial regression analysis.

RESULTS

Among 3 470 905 adults (1 823 816 female [52.5%]) with inpatient hospitalizations for major surgery, 70 752 (2.0%) were Asian, 453 428 (13.1%) were Black, 2 696 929 (77.7%) were White, and 249 796 (7.2%) were individuals of other races. The number of monthly elective cases during the first wave was 49% (incident rate ratio [IRR], 0.49; 95% CI, 0.486-0.492; P < .001) compared with the baseline period. The relative reduction in unadjusted elective surgery cases for Black (unadjusted IRR, 0.99; 95% CI, 0.97-1.01; P = .36), Asian (unadjusted IRR, 1.08; 95% CI, 1.03-1.14; P = .001), and other race individuals (unadjusted IRR, 0.97; 95% CI, 0.95-1.00; P = .05) during the surge period compared with the baseline period was very close to the change in cases for White individuals. After adjustment for age, sex, comorbidities, and surgical procedure, there was still no evidence that the first wave of the pandemic was associated with disparities in access to elective surgery.

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, the CMS's moratorium on nonessential operations was associated with a 51% reduction in elective operations. It was not associated with greater reductions in operations for racial minority individuals than for White individuals. This evidence suggests that the early response to the pandemic did not increase disparities in access to surgical care.

Influence of aneurysmal aortic root geometry on mechanical stress to the aortic valve leaflet

AIMS

While mechanical stress caused by blood flow, e.g. wall shear stress (WSS), and related parameters, e.g. oscillatory shear index (OSI), are increasingly being recognized as key moderators of various cardiovascular diseases, studies on valves have been limited because of a lack of appropriate imaging modalities. We investigated the influence of aortic root geometry on WSS and OSI on the aortic valve (AV) leaflet.

METHODS AND RESULTS

We applied our novel approach of intraoperative epi-aortic echocardiogram to measure the haemodynamic parameters of WSS and OSI on the AV leaflet. Thirty-six patients were included, which included those who underwent valve-sparing aortic root replacement (VSARR) with no significant aortic regurgitation (n = 17) and coronary artery bypass graft (CABG) with normal AV (n = 19). At baseline, those who underwent VSARR had a higher systolic WSS (0.52 ± 0.12 vs. 0.32 ± 0.08 Pa, respectively, P < 0.001) and a higher OSI (0.37 ± 0.06 vs. 0.29 ± 0.04, respectively, P < 0.001) on the aortic side of the AV leaflet than those who underwent CABG. Multivariate regression analysis revealed that the size of the sinus of Valsalva had a significant association with WSS and OSI. Following VSARR, WSS and OSI values decreased significantly compared with the baseline values (WSS: 0.29 ± 0.12 Pa, P < 0.001; OSI: 0.26 ± 0.09, P < 0.001), and became comparable to the values in those who underwent CABG (WSS, P = 0.42; OSI, P = 0.15).

CONCLUSIONS

Mechanical stress on the AV gets altered in correlation with the size of the aortic root. An aneurysmal aortic root may expose the leaflet to abnormal fluid dynamics. The VSARR procedure appeared to reduce these abnormalities.

Mitral Regurgitation in 2020: The 2020 Focused Update of the 2017 American College of Cardiology Expert Consensus Decision Pathway on the Management of Mitral Regurgitation

The recently published "2020 Focused Update of the 2017 ACC Expert Consensus Decision Pathway on the Management of Mitral Regurgitation" provides a framework for the clinical and echocardiographic assessment of mitral regurgitation and describes considerations for the medical, surgical, and transcatheter treatment of mitral regurgitation. The Update provides guidance for clinicians in light of the significant interim developments since the 2017 recommendations, particularly in the areas of secondary mitral regurgitation and transcatheter mitral valve repair. The present review focuses on the aspects of the Update that are most relevant to the cardiac anesthesiologist, with emphasis on the integrated assessment of mitral regurgitation with echocardiography and the indications and considerations for the surgical and transcatheter management of mitral regurgitation.

A novel in vivo assessment of fluid dynamics on aortic valve leaflet using epi-aortic echocardiogram

BACKGROUND

Mechanical stress caused by blood flow, such as wall shear stress (WSS) and its related parameters, is key moderator of endothelial degeneration. However, an in vivo method to measure WSS on heart valves has not been developed.

METHODS

We developed a novel approach, based on vector flow mapping using intraoperative epi-aortic echocardiogram, to measure WSS and oscillatory shear index (OSI) on the aortic valve. We prospectively enrolled 15 patients with normal valves, who underwent coronary artery bypass graft.

RESULTS

Systolic WSS on the ventricularis (2.40 ± 0.44 Pa [1.45-3.00 Pa]) was higher than systolic WSS on the fibrosa (0.33 ± 0.08 Pa [0.14-0.47 Pa], P < .001) and diastolic WSS on the ventricularis (0.18 ± 0.07 Pa [0.04-0.28 Pa], P < .001). Oscillatory shear index on the fibrosa was higher than on the ventricularis (0.29 ± 0.04 [0.24-0.36] vs 0.05 ± 0.03 [0.01-0.12], P < .001). A pilot study involving two patients with severe aortic regurgitation showed significantly different values in fluid dynamics.

CONCLUSION

Vector flow mapping method using intraoperative epi-aortic echocardiogram is an effective way of measuring WSS and OSI on normal aortic leaflet in vivo, allowing for better understanding of the pathophysiology of aortic valve diseases.

Imaging in patients with severe mitral annular calcification: insights from a multicentre experience using transatrial balloon-expandable valve replacement

Aims

To investigate valve sizing and the haemodynamic relevance of the predicted left ventricular outflow tract (LVOT) in patients with mitral annular calcification (MAC) undergoing transatrial transcatheter valve implantation (THV).

Methods and results

In total, 21 patients undergoing transatrial THV, multiplanar reconstruction (MPR), maximum intensity projection (MIP), and cubic spline interpolation (CSI) were compared for MA sizing during diastole. In addition, predicted neo-LVOT areas were measured in 18 patients and correlated with the post-procedural haemodynamic dimensions. The procedure was successful in all patients (100%). Concomitant aortic valve replacement was performed in eight patients (43%) (AVR group). Sizing using MPR and MIP yielded comparable results in terms of area, perimeter, and diameter, whereas the dimensions obtained with CSI were systematically smaller. The simulated mean systolic neo-LVOT area was 133.4 ± 64.2 mm2 with an anticipated relative LVOT area reduction (neo-LVOT area/LVOT area × 100) of 59.3 ± 14.7%. The systolic relative LVOT area reduction, but not the absolute neo-LVOT area, was found to predict the peak (r = 0.69; P = 0.002) and mean (r = 0.65; P = 0.004) post-operative aortic gradient in the overall population as well as separately in the AVR (peak: r = 0.91; P = 0.002/mean: r = 0.85; P = 0.002) and no-AVR (peak: r = 0.89; P = 0.003/mean: r = 0.72; P = 0.008) groups.

Conclusion

In patients with severe MAC undergoing transatrial transcatheter valve implantation, MPR, and MIP yielded comparable annular dimensions, while values obtained with CSI tended to be systematically smaller. Mitral annular area and the average annular diameter appear to be reliable parameters for valve selection. Simulated relative LVOT reduction was found to predict the post-procedural aortic gradients.

Evaluation of low-cost computer monitors for the detection of cervical spine injuries in the emergency room: an observer confidence-based study

BACKGROUND

To compare the diagnostic value of low-cost computer monitors and a Picture Archiving and Communication System (PACS) workstation for the evaluation of cervical spine fractures in the emergency room.

METHODS

Two groups of readers blinded to the diagnoses (2 radiologists and 3 orthopaedic surgeons) independently assessed-digital radiographs of the cervical spine (anterior-posterior, oblique and trans-oral-dens views). The radiographs of 57 patients who arrived consecutively to the emergency room in 2004 with clinical suspicion of a cervical spine injury were evaluated. The diagnostic values of these radiographs were scored on a 3-point scale (1 = diagnosis not possible/bad image quality, 2 = diagnosis uncertain, 3 = clear diagnosis of fracture or no fracture) on a PACS workstation and on two different liquid crystal display (LCD) personal computer monitors. The images were randomised to avoid memory effects. We used logistic mixed-effects models to determine the possible effects of monitor type on the evaluation of x ray images. To determine the overall effects of monitor type, this variable was used as a fixed effect, and the image number and reader group (radiologist or orthopaedic surgeon) were used as random effects on display quality. Group-specific effects were examined, with the reader group and additional fixed effects as terms. A significance level of 0.05 was established for assessing the contribution of each fixed effect to the model.

RESULTS

Overall, the diagnostic score did not differ significantly between standard personal computer monitors and the PACS workstation (both p values were 0.78).

CONCLUSION

Low-cost LCD personal computer monitors may be useful in establishing a diagnosis of cervical spine fractures in the emergency room.