We describe the clinical course and treatment of a 53-year-old female, with small chest dimensions, referred to our institution for a primary cardiogenic shock. The patient underwent an on-pump left ...ventricular assist-device (VAD) implantation with the aid of immediate post-operative paracorporeal right-VAD assistance for an acute right ventricular failure. After two unsuccessful weaning attempts, she underwent extrapericardial HM 3 RVAD implantation.
Propensity score matching is a statistical method that is often used to make inferences on the treatment effects in observational studies. In recent years, there has been widespread use of the ...technique in the cardiothoracic surgery literature to evaluate to potential benefits of new surgical therapies or procedures. However, the small sample size and the strong dependence of the treatment assignment on the baseline covariates that often characterize these studies make such an evaluation challenging from a statistical point of view. In such settings, the use of propensity score matching in combination with oversampling and replacement may provide a solution to these issues by increasing the initial sample size of the study and thus improving the statistical power that is needed to detect the effect of interest. In this study, we review the use of propensity score matching in combination with oversampling and replacement in small sample size settings.
We performed a series of Monte Carlo simulations to evaluate how the sample size, the proportion of treated, and the assignment mechanism affect the performances of the proposed approaches. We assessed the performances with overall balance, relative bias, root mean squared error and nominal coverage. Moreover, we illustrate the methods using a real case study from the cardiac surgery literature.
Matching without replacement produced estimates with lower bias and better nominal coverage than matching with replacement when 1:1 matching was considered. In contrast to that, matching with replacement showed better balance, relative bias, and root mean squared error than matching without replacement for increasing levels of oversampling. The best nominal coverage was obtained by using the estimator that accounts for uncertainty in the matching procedure on sets of units obtained after matching with replacement.
The use of replacement provides the most reliable treatment effect estimates and that no more than 1 or 2 units from the control group should be matched to each treated observation. Moreover, the variance estimator that accounts for the uncertainty in the matching procedure should be used to estimate the treatment effect.
Different left ventricular assist devices (LVADs) are provided of different driveline exit sites: HeartWare HVAD presents abdominal power-cable-supply, while the Jarvik 2000 LVAD is powered by a ...retroauricular driveline. We analyzed 93 LVAD-implanted patients from January-2009 to October-2016 (41 HeartWare and 52 Jarvik 2000), hypothesizing a different incidence of infection, according to driveline exit site. The two populations were propensity matched for the demographic data and preoperative variables, and the outcomes were further analyzed. Nine driveline infections (DLIs) were in each LVAD group recorded (22% for HVAD and 17% for Jarvik 2000). The incidence of the complication was similar between groups (
p
= 0.97), even during time (
p
= 0.27 within 6 months and
p
= 0.16 over 6 months of support). Age at implant (
p
= 0.01), revision for bleeding (
p
= 0.05), days of postoperative intubation (
p
= 0.002), and ICU stay (
p
< 0.001), as well as days on device (
p
< 0.001) were identified as risk factors for DLIs. The type of device and the driveline exit site were not statistically co-related to infections. Similar infection-freedom survival was identified (
p
= 0.87). Younger age at implant, revision for bleeding, prolonged mechanical ventilation, delayed rehabilitation, as well as long time LVAD support were identified as risk factors for exit site DLIs. Despite similar incidence of DLIs, the different management and care of the retroauricular exit site makes it more appropriate and comfortable in long-term support.
Abstract Background The role of extracorporeal life support (ECLS) in primary cardiogenic shock (PCS) is well established. In this study, we evaluated the impact of etiology on outcomes. Methods ...Between January 2009 and March 2013, we implanted a total of 249 patients with ECLS; we focused on 64 patients for whom peripheral ECLS was the treatment for PCS. Of these, 37 cases (58%) were “acute” (mostly acute myocardial infarction: 39%); 27 (42%) had an exacerbation of “chronic” heart failure (dilated cardiomyopathy: 30%; post-ischemic cardiomyopathy: 9%; and congenital: 3%). Results In the group with chronic etiology, 23 patients were bridged to a left ventricular assist device (52%) or heart transplantation (33%). In the group with acute etiology, ECLS was used as a bridge-to-transplantation in 3 patients (8%), a bridge-to-bridge in 9 (24%), and a bridge-to-recovery in 18 (49%). One patient in each group was bridged to conventional surgery. Recovery of cardiac function was achieved in only the group with acute primary cardiogenic shock (18 vs 0 patients, P = .0001). A mean flow during support of ≤60% of the theoretic flow (body surface area × 2.4) was a predictor of successful weaning ( P = .02). Median duration of ECLS support was 7 days (range: 2-11.5 days). Nine patients (14%) died during support; 30-day overall survival was 80% (51 of 64 patients); and 59% of patients were discharged, in whom survival at 48 months was 90%. Thirty-day survival was correlated with duration of ECLS support. Conclusions In “chronic” heart failure, ECLS represents a bridge to a ventricular assist device or heart transplantation, whereas in “acute” settings, it offers a considerable chance of recovery, and is often the only required therapy.
Extracorporeal membrane oxygenation (ECMO) has been increasingly used in the last years to provide hemodynamic and respiratory support in critically ill patients. In this scenario, prognostic scores ...remain essential to choose which patients should initiate ECMO. This systematic review aims to assess the current landscape and inform subsequent efforts in the development of risk prediction tools for ECMO.
PubMed, CINAHL, Embase, MEDLINE and Scopus were consulted. Articles between Jan 2011 and Feb 2022, including adults undergoing ECMO reporting a newly developed and validated predictive model for mortality, were included. Studies based on animal models, systematic reviews, case reports and conference abstracts were excluded. Data extraction aimed to capture study characteristics, risk model characteristics and model performance. The risk of bias was evaluated through the prediction model risk-of-bias assessment tool (PROBAST). The protocol has been registered in Open Science Framework ( https://osf.io/fevw5 ).
Twenty-six prognostic scores for in-hospital mortality were identified, with a study size ranging from 60 to 4557 patients. The most common candidate variables were age, lactate concentration, creatinine concentration, bilirubin concentration and days in mechanical ventilation prior to ECMO. Five out of 16 venous-arterial (VA)-ECMO scores and 3 out of 9 veno-venous (VV)-ECMO scores had been validated externally. Additionally, one score was developed for both VA and VV populations. No score was judged at low risk of bias.
Most models have not been validated externally and apply after ECMO initiation; thus, some uncertainty whether ECMO should be initiated still remains. It has yet to be determined whether and to what extent a new methodological perspective may enhance the performance of predictive models for ECMO, with the ultimate goal to implement a model that positively influences patient outcomes.
Increasing left ventricular assist device (LVAD) pump speed according to the patient's activity is a fascinating hypothesis. This study analyzed the short-term effects of LVAD speed increase on ...cardiopulmonary exercise test (CPET) performance, muscle oxygenation (near-infrared spectroscopy), diffusion capacity of the lung for carbon monoxide (Dlco) and nitric oxide (Dlno), and sleep quality.
We analyzed CPET, Dlco and Dlno, and sleep in 33 patients supported with the Jarvik 2000 (Jarvik Heart Inc., New York, NY). After a maximal CPET (n = 28), patients underwent 2 maximal CPETs with LVAD speed randomly set at 3 or increased from 3 to 5 during effort (n = 15). Then, at LVAD speed randomly set at 2 or 4, we performed (1) constant workload CPETs assessing O
kinetics, cardiac output (CO), and muscle oxygenation (n = 15); (2) resting Dlco and Dlno (n = 18); and (3) nocturnal cardiorespiratory monitoring (n = 29).
The progressive pump speed increase raised peak volume of oxygen consumption (12.5 ± 2.5 ml/min/kg vs 11.7 ± 2.8 ml/min/kg at speed 3; p = 0.001). During constant workload, from speed 2 to 4, CO increased (at rest: 3.18 ± 0.76 liters/min vs 3.69 ± 0.75 liters/min, p = 0.015; during exercise: 5.91 ± 1.31 liters/min vs 6.69 ± 0.99 liters/min, p = 0.014), and system efficiency (τ = 65.8 ± 15.1 seconds vs 49.9 ± 14.8 seconds, p = 0.002) and muscle oxygenation improved. At speed 4, Dlco decreased, and obstructive apneas increased despite a significant apnea/hypopnea index and a reduction of central apneas.
Short-term LVAD speed increase improves exercise performance, CO, O
kinetics, and muscle oxygenation. However, it deteriorates lung diffusion and increases obstructive apneas, likely due to an increase of intrathoracic fluids. Self-adjusting LVAD speed is a fascinating but possibly unsafe option, probably requiring a monitoring of intrathoracic fluids.
Transcatheter aortic valve implantation plays a leading role in the management of aortic stenosis in patients with comorbidities but no data are available about cardiac rehabilitation in these ...subjects. This study aimed to compare safety and efficacy of an early, exercise-based, cardiac rehabilitation programme in octogenarians after a traditional surgical aortic valve replacement versus transcatheter aortic valve implantation.
Seventy-eight consecutive transcatheter aortic valve implantation patients were studied in order to evaluate the effect of an exercise-based cardiac rehabilitation programme in comparison to 80 of a similar age having surgical aortic valve replacement. Functional capacity was assessed by a 6 min walking test on admission and at the end of the programme. When possible, a cardiopulmonary exercise test was also performed before discharge.
The two groups were similar in terms of gender and length of stay in cardiac rehabilitation; as expected, the transcatheter aortic valve implantation group had more comorbidities but no major complications occurred in either group during rehabilitation. All patients enhanced autonomy and mobility and were able to walk at least with the assistance of a stick. In those patients who were able to perform the 6 min walking test, the distance walked at discharge did not significantly differ between the groups (272.7 ± 108 vs. 294.2 ± 101 m, p = 0.42), neither did the exercise capacity assessed by cardiopulmonary exercise test (peak-VO2 12.5 ± 3.6 vs. 13.9 ± 2.7 ml/kg/min, p = 0.16).
Cardiac rehabilitation is feasible, safe and effective in octogenarian patients after transcatheter aortic valve implantation as well as after traditional surgery. An early cardiac rehabilitation programme enhances independence, mobility and functional capacity and should be highly encouraged.
Two well‐characterized carbohydrate epitopes are absent in humans but present in other mammals. These are galactose‐α1,3‐galactose (αGal) and N‐glycolylneuraminic acid (Neu5Gc) which are introduced ...by the activities of two enzymes including α(1,3) galactosyltransferase (encoded by the GGTA1 gene) and CMP‐Neu5Gc hydroxylase (encoded by the CMAH gene) that are inactive in humans but present in cattle. Hence, bovine‐derived products are antigenic in humans who receive bioprosthetic heart valves (BHVs) or those that suffer from red meat syndrome. Using programmable nucleases, we disrupted (knockout, KO) GGTA1 and CMAH genes encoding for the enzymes that catalyse the synthesis of αGal and Neu5Gc, respectively, in both male and female bovine fibroblasts. The KO in clonally selected fibroblasts was detected by polymerase chain reaction (PCR) and confirmed by Sanger sequencing. Selected fibroblasts colonies were used for somatic cell nuclear transfer (SCNT) to produce cloned embryos that were implanted in surrogate recipient heifers. Fifty‐three embryos were implanted in 33 recipients heifers; 3 pregnancies were carried to term and delivered 3 live calves. Primary cell cultures were established from the 3 calves and following molecular analyses confirmed the genetic deletions. FACS analysis showed the double‐KO phenotype for both antigens confirming the mutated genotypes. Availability of such cattle double‐KO model lacking both αGal and Neu5Gc offers a unique opportunity to study the functionality of BHV manufactured with tissues of potentially lower immunogenicity, as well as a possible new clinical approaches to help patients with red meat allergy syndrome due to the presence of these xenoantigens in the diet.
The cause of structural valve deterioration (SVD) is unclear. Therefore, we investigated oxidative stress markers in sera from patients with bioprosthetic heart valves (BHVs) and their association ...with SVD. Blood samples were taken from SVD (Phase A) and BHV patients during the first 24 (Phase B1) and >48 months (Phase B2) after BHV implantation to assess total antioxidant capacity (TAC), malondialdehyde (MDA), and nitrotyrosine (NT). The results show that MDA levels increased significantly 1 month after surgery in all groups but were higher at 6 months only in incipient SVD patients. NT levels increased gradually for the first 24 months after implantation in the BHV group. Patients with transcatheter aortic valve implantation (TAVI) showed even higher levels of stress markers. After >48 months, MDA and NT continued to increase in BHV patients with a further elevation after 60–72 months; however, these levels were significantly lower in the incipient and established SVD groups. In conclusion, oxidative stress may play a significant role in SVD, increasing early after BHV implantation, especially in TAVI cases, and also after 48 months’ follow-up, but decreasing when SVD develops. Oxidative stress potentially represents a target of therapeutic intervention and a biomarker of BHV dysfunction.
...the hemodynamic pattern was likely different. ...patients with HF with elevated AHI and several CSAs have the same cardiac output and circulatory delay as patients who do not show these findings ...(1). ...changes in AHI are unlikely related to changes in pulmonary receptor stimulation.
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