Echocardiographic haemodynamic monitoring in the context of HeartMate 3™ therapy: a systematic review.

AIMS: While echocardiography remains essential within haemodynamic monitoring of durable mechanical circulatory support, previous echocardiographic guidelines are missing scientific evidence for the novel HeartMate 3™ (HM3) system. Accordingly, this review aims to summarize available echocardiographic evidence including HM3. METHODS AND RESULTS: This systematic review adhered to the PRISMA 2020 guidelines. Searches were conducted during August 2023 across PubMed, Embase, and Google Scholar using specific echocardiographic terms combined with system identifiers. Study quality was assessed using the Newcastle-Ottawa Scale (NOS) for cohort studies and Critical Appraisal Instrument (PCAI) for cross-sectional studies. Nine studies met the inclusion criteria, of which eight cohort studies and one cross-sectional study. Aortic regurgitation (AR) prevalence at approximately 12 months of support exhibited heterogenicity (33.5% (Δ 33%)) in a limited number of studies (n = 3). Several studies (n = 5) demonstrated an increasing prevalence and severity of AR during HM3 support, generating moderate to high level of evidence. One AR study showed a higher cumulative incidence of death and heart failure (HF) readmission compared with those without significant AR, hazard ratio 3.42 (95% CI 1.48-8.76). A second study showed that a worsening AR group had significantly lower survival-free from HF readmission (59% vs. 89%, P = 0.023) with a hazard ratio of 5.18 (95% CI 1.07-25.0), while a third study did not reveal any differences in cardiac-related hospitalizations in the 12 months follow-up or non-cardiac-related hospitalization. Mitral regurgitation (MR) prevalence at approximately 12 months of support exhibited good consistency 15.0% (Δ 0.8%) in both included studies, which did not reveal any significant pattern of changing prevalence over time. Tricuspid regurgitation (TR) prevalence at approximately 12 months of support exhibited fair consistency 28.5% (Δ 8.3%) in a limited number of studies (n = 2); both studies showed a statistically un-confirmed trend of increased TR prevalence over time. The evidence of general prevalence of right ventricular dysfunction (RVD) was insufficient due to lack of studies. CONCLUSIONS: There are few methodologically consistent studies with focus on long-term haemodynamic effects. Aortic regurgitation still seems to be a prevalent and potentially significant finding. The available evidence concerning right heart function is limited despite clinical relevance and potential prognostic value. Potential interventricular and haemodynamic interplay are identified as a white field for future research.

Right ventricular function in severe aortic stenosis assessed by echocardiography and MRI.

BACKGROUND: The prevalence of aortic valve stenosis (AS) is increasing due to an ageing population. Despite that right ventricular function has prognostic value for postoperative outcome, the right ventricle (RV) is not extensively studied and often not routinely assessed in AS. Our aim was to explore the relation between severe AS and RV function in a surgical aortic valve replacement (SAVR) cohort, comparing two imaging modalities for RV evaluation. METHODS: Patients with severe AS, underwent cardiovascular magnetic resonance imaging (CMR) and transthoracic echocardiography (TTE) before SAVR. RV dysfunction was defined as one or more of the following: tricuspid annular plane systolic excursion (TAPSE) < 17 mm, RV free wall strain (RVFWS) > -20% by TTE and RV ejection fraction (RVEF) <50% by CMR. RESULTS: Sixteen (33%) patients were found to have RV dysfunction. Patients with RV dysfunction showed significantly lower indexed aortic valve area, left ventricular (LV) ejection fraction as well as RV and LV stroke volumes compared to patients with maintained RV function. All patients with reduced RVEF also had changes in TAPSE or RVFWS and a larger number of patients had a reduced longitudinal RV function despite a normal RVEF. CONCLUSION: In a SAVR cohort one-third of the patients had RV dysfunction, defined by RVEF, TAPSE or RVFW strain. Echocardiography detected subtle changes in RV function before RVEF was reduced. It is likely that the more pronounced the AS, the more frequent the occurrence of RV dysfunction.

Reconstruction of sternal defects after sternotomy with postoperative osteomyelitis, using a unilateral pectoralis major advancement muscle flap.

BACKGROUND: The pectoralis major flap, which is usually harvested bilaterally, is considered a workhorse flap in the reconstruction of sternal defects. After a median sternotomy for open heart surgery, 1%-3% of patients develop deep infection and dehiscence of the sternal wound, some of which will eventually require reconstructive surgery. Our aim was to describe the clinical feasibility and associated complications of the unilateral pectoralis major advancement flap in the reconstruction of sternal defects. METHODS: A retrospective analysis of all adult patients who were operated on using a unilateral pectoralis major flap for reconstruction of the chest wall at the Linköping University Hospital during 2008-18 was made using data retrieved from medical records. RESULTS: Forty-three patients had reconstructions with unilateral pectoralis major flaps. Three flaps failed completely, and another 10 patients developed complications that required further operation. The factors that were independently associated with loss of the flaps and complications were: older age, male sex, the number of different antibiotics used, and a long duration of treatment with negative wound pressure. Fewer wound revisions before the reconstruction resulted in more complications. The factors that were independently associated with prolonged time to complete healing were emergency reoperation after the initial operation and complications after reconstruction. CONCLUSION: The unilateral pectoralis major advancement flap has proved to be a useful technique in the reconstruction of most sternal defects after sternal wound infection in older patients. There is, however, need for a follow-up study on a larger number of procedures to evaluate the long-term outcome compared with other methods of sternal reconstruction.

Sound analysis of the magnetically levitated left ventricular assist device HeartMate 3™.

INTRODUCTION: The HeartMate 3™ has shown lower rates of adverse events compared to previous devices due to the design and absence of mechanical bearings. For previous devices, sound analysis emerged as a way to assess pump function. The aims of this study were to determine if sound analysis can be applied to the HeartMate 3 in vivo and in vitro and to evaluate an electronic stethoscope. METHOD: Sound recordings were performed with microphones and clinical accessible electronic stethoscope. The recordings were studied in both the time and the frequency domains. Recordings from four patients were performed to determine if in vivo and in vitro recordings are comparable. RESULTS: The results show that it is possible to detect sound from HeartMate 3 and the sound spectrum is clear. Pump frequency and frequency of the pulsatile mode are easily determined. Frequency spectra from in vitro and in vivo recordings have the same pattern, and the major proportion (96.7%) of signal power is located at the pump speed frequency ±40 Hz. The recordings from the patients show low inter-individual differences except from location of peaks originating from pump speed and harmonics. Electronic stethoscopes could be used for sound recordings, but the dedicated equipment showed a clearer sound spectrum. DISCUSSION: The results show that acoustic analysis can also be performed with the HeartMate 3 and that in vivo and in vitro sound spectrum is similar. The frequency spectra are different from previous devices, and methods for assessing pump function or thrombosis need further evaluation.

Sound analysis of a left ventricular assist device: A technical evaluation of iOS devices.

INTRODUCTION: The use of left ventricular assist device (LVAD) has grown rapidly. Adverse events do continue to occur. In recent years, analysis of LVAD sound recordings emerged as a means to monitor pump function and detect pump thrombosis. The aim of this study was to characterize the sounds from HeartMate II and to evaluate the use of handheld iOS devices for sound recordings. METHOD: Signal analysis of LVAD sound recordings, with dedicated recording equipment and iOS devices, was performed. Two LVADs running in mock loop circuits were compared to an implanted LVAD. Spectral analysis and parametric signal models were explored to quantify the sound and potentially detect changes in it. RESULTS: The sound recordings of two LVADs in individual mock loop circuits and a third one implanted in a patient appeared to be similar. Qualitatively, sound characteristics were preserved following changes in pump speed. Recordings using dedicated equipment showed that HeartMate II sound comprises low-frequency components corresponding to pump impeller rotation, as well as high-frequency components due to a pulse width modulation of the electric power to the pump. These different signal components interact and result in a complicated frequency spectrum. The iPhone and iPod recordings could not reproduce the sounds as well as the dedicated equipment. In particular, lower frequencies were affected by outside disturbances. DISCUSSION: This article outlines a systematic approach to LVAD sound analysis using signal processing methods to quantify and potentially detect changes, and describes some of the challenges, for example, with the use of inexpensive recording devices.

Validity of the Swedish Cardiac Surgery Registry.

OBJECTIVES: Our goal was to validate the Swedish Cardiac Surgery Registry by reviewing the reported cardiac operations to assess the completeness and quality of the registered data and the EuroSCORE II variables. METHODS: A total of 5837 cardiac operations were reported to the Swedish Cardiac Surgery Registry in Sweden during 2015. A randomly selected sample of 753 patient records (13%) was scrutinized by 3 surgeons at all 8 units in Sweden performing open cardiac surgery in adults. RESULTS: Coverage was excellent with 99% [95% confidence interval (CI) 98-99%] of the performed procedures found in the registry. Reported waiting times for surgery were correct in 78% (95% CI 76-79%) of the cases. The main procedural code was correctly reported in 96% (95% CI 95-97%) of the cases. The correlation between reported and monitored logistic EuroSCORE II had a coefficient of 0.79 (95% CI 0.76-0.82), and the median difference in EuroSCORE II was 0% (interquartile range -0.4% to 0.4%). The majority of EuroSCORE II variables had good agreement and coherence; however, New York Heart Association functional class, preoperative renal dysfunction, left ventricular ejection fraction, Canadian Cardiovascular Society Class IV angina and poor mobility were less robust. Postoperative complications were rare and in general had a high degree of completeness and agreement. CONCLUSIONS: The reliability of the variables in the national Swedish Cardiac Surgery Registry was excellent. Thus, the registry is a valuable source of data for quality studies and research. Some EuroSCORE II variables require improved and stricter definitions to obtain uniform reporting and high validity.

Young woman with breast cancer and cardiotoxicity with severe heart failure treated with a HeartMate IITM for nearly 6 years before heart transplantation.

Cardiotoxicity is a multifactorial problem, which has emerged with the improvement of cancer therapies and survival. Heart transplantation is relatively contraindicated in patients with breast cancer, until at least 5 years after complete remission. We present a case where a young woman who in 2001, at the age of 31, was diagnosed with breast cancer. She was considered cured, but 4 years later she suffered a relapse. During her second treatment, in 2006, she suffered from severe heart failure. She received a HeartMate II, as a long-term bridge to transplantation and 6 years later she was successfully transplanted. In this case report we discuss the use of mechanical circulatory support in cancer patients with drug-induced heart failure.

Acoustic analysis of a mechanical circulatory support.

Mechanical circulatory support technology is continually improving. However, adverse complications do occur with devastating consequences, for example, pump thrombosis that may develop in several parts of the pump system. The aim of this study was to design an experimental clot/thrombosis model to register and analyze acoustic signals from the left ventricular assist device (LVAD) HeartMate II (HMII) (Thoratec Corporation, Inc., Pleasanton, CA, USA) and detect changes in sound signals correlating to clots in the inflow, outflow, and pump housing. Using modern telecom techniques, it was possible to register and analyze the HMII pump-specific acoustic fingerprint in an experimental model of LVAD support using a mock loop. Increase in pump speed significantly (P<0.005) changed the acoustic fingerprint at certain frequency (0-23,000 Hz) intervals (regions: R1-3 and peaks: P1,3-4). When the ball valves connected to the tubing were narrowed sequentially by ∼50% of the inner diameter (to mimic clot in the out- and inflow tubing), the frequency spectrum changed significantly (P<0.005) in P1 and P2 and R1 when the outflow tubing was narrowed. This change was not seen to the same extent when the lumen of the ball valve connected to the inflow tube was narrowed by ∼50%. More significant (P<0.005) acoustic changes were detected in P1 and P2 and R1 and R3, with the largest dB figs. in the lower frequency ranges in R1 and P2, when artificial clots and blood clots passed through the pump system. At higher frequencies, a significant change in dB figs. in R3 and P4 was detected when clots passed through the pump system. Acoustic monitoring of pump sounds may become a valuable tool in LVAD surveillance.

Long-term left ventricular support in patients with a mechanical aortic valve.

OBJECTIVES: The presence of a mechanical prosthesis has been regarded as an increased risk of thromboembolic complications and as a relative contraindication for a left ventricular assist device (LVAD). Five patients in our center had a mechanical aortic valve at the time of device implantation and were studied regarding thromboembolic complications. DESIGN: Five patients operated upon with an LVAD (1 HeartMate I™, 4 HeartMate II™) between 2002 and 2011 had a mechanical aortic valve at the time of implantation. The first patient had a patch closure of the aortic valve. In four patients, the prosthesis was left in place. Anticoagulants included aspirin, warfarin, and clopidogrel. RESULTS: The average and accumulated treatment times were 150 and 752 days, respectively. Three of the five patients showed early signs of valve thrombosis on echo with concomitant valve dysfunction. Four patients were transplanted without thromboembolic events during pump treatment. One patient died from a hemorrhagic stroke after 90 days on the LVAD. CONCLUSIONS: The strategy of leaving a mechanical heart valve in place at the time of LVAD implantation in five patients led to valvular thrombosis in three but did not provoke embolic events. It increased the complexity of postoperative anticoagulation.

A single center experience with the HeartMate II left ventricular assist device (LVAD).

OBJECTIVES: Left ventricular assist devices (LVAD), used in the setting bridge-to-transplantation and destination therapy, for patients with deteriorating severe heart failure are continuously developing. The second generation, the axial flow pumps, have been introduced since some years. DESIGN: Eleven consecutive patients, seven male, with severe heart failure due to ischemic cardiomyopathy (n=5), dilated cardiomyopathy (n=5) and cytotoxic etiology (n=1) were implanted with the HeartMate-II. They were preoperatively treated with inotropic support (n=9), ventricular assist device (n=2) and mechanical ventilation (n=4). RESULTS: Eight patients were bridged to transplant after median 155 days (range, 65 to 316 days). One patient is ongoing for 748 days, intended for destination therapy. Ten of eleven patients were discharged after median 64 days (range, 40 to 105 days). Four patients were reoperated due to bleeding. Two embolic events were recorded. One perioperative death. CONCLUSION: Eleven HM-II LVAD's have been implanted in our institution with good early results. Eight patients were successfully bridged to heart transplantation. One patient is intended for destination therapy and is ongoing since November 2006. In these severely ill patients, this technique offers a good chance surviving until heart transplantation. In selected cases the technique also offers the possibility of a permanent support and longevity.

Experience with the Impella recovery axial-flow system for acute heart failure at three cardiothoracic centers in Sweden.

OBJECTIVES: The Impella recovery axial-flow system is a mechanical assist system for use in acute heart failure. This retrospective study reports the use of the device at three cardiothoracic units in Sweden. DESIGN: Fifty patients (35 men, mean age 55.8 years, range 26 to 84 years) underwent implantation of 26 ImpellaLP 2.5/5.0 (support-time 0.1 to 14 days), 16 ImpellaLD (support-time 1 to 7 days) and 8 ImpellaRD (support-time 0.1 to 8 days) between 2003 and 2007. Implantation was performed because of postcardiotomy heart failure (surgical group, n=33) or for various states of heart failure in cardiological patients (non-surgical group, n=17). The intention for the treatments was mainly to use the pump as a "bridge-to-recovery". RESULTS: Early mortality in the surgical and non-surgical groups was 45% and 23%, respectively. Complications included infection, 36% and right ventricular failure, 28%. Cardiac output and cardiac power output postoperatively were significantly higher among survivors than non-survivors. CONCLUSIONS: The Impella recovery axial-flow system facilitates treatment in acute heart failure. Early intervention in patients with acute heart failure and optimized hemodynamics in the post-implantation period seem to be of importance for long-term survival. Insufficient early response to therapy should urge to consider further treatment options.

Cost effectiveness of local collagen-gentamicin as prophylaxis for sternal wound infections in different risk groups.

OBJECTIVES: In a randomized trial addition of local collagen-gentamicin in the sternal wound reduced the rate of sternal wound infection (SWI) to about 50% compared to intravenous prophylaxis alone. The aim of the present study was to evaluate the economic rationale for its use in every-day clinical practice. This includes the question whether high-risk groups that may have particular benefit should be identified. DESIGN: For each patient with SWI in the trial the costs attributable to the SWI were calculated. Risk factors for SWI were identified and any heterogeneity of the effect of the prophylaxis examined. RESULTS: The mean cost of a SWI was about 14500 Euros. A cost effectiveness analysis showed that the prophylaxis was cost saving. The positive net balance was even higher in risk groups. Assignment to the control group, overweight, diabetes, younger age, mammarian artery use, left ventricular ejection fraction <35% and longer operation time were independent risk factors for infection. CONCLUSION: The addition of local collagen-gentamicin to intravenous antibiotic prophylaxis was dominant, i.e. resulted in both lower costs and fewer wound infections.

Local gentamicin reduces sternal wound infections after cardiac surgery: a randomized controlled trial.

BACKGROUND: Sternal wound infections remain a major cause of morbidity after cardiac surgery. Vancomycin is often the only effective antibiotic available for their treatment but its use for routine prophylaxis is inadvisable for ecological reasons. Local application of gentamicin produces high antibiotic concentrations in the wound. We aimed to determine whether this treatment could have an additive effect on the incidence of sternal wound infections when combined with routine prophylaxis. METHODS: Two thousand cardiac surgery patients were randomized to routine prophylaxis with intravenous isoxazolyl-penicillin alone (control group) or to this prophylaxis combined with application of collagen-gentamicin (260 mg gentamicin) sponges within the sternotomy before wound closure. Endpoint was any sternal wound infection within 2 months postoperatively. Evaluations were double-blind and made on an intention-to-treat basis. RESULTS: Evaluation was possible in 967 and 983 patients in the control and treatment groups, respectively. The incidence of sternal wound infection was 4.3% in the treatment group and 9.0% in the control group (relative risk 0.47; 95% confidence interval 0.33-0.68; p < 0.001). Early reoperation for bleeding was more common in the treatment group (4.0% vs 2.3%, p = 0.03). No difference in postoperative renal function was noted. CONCLUSIONS: Local collagen-gentamicin reduced the risk for postoperative sternal wound infections. Further studies are warranted to confirm these results, particularly with regard to deep infections.

Report generation and data mining in the domain of thoracic surgery.

As a part of AssistMe system, the reporting system has been developed for the thoracic surgery domain. Reporting System is defined as software for dynamic report generation purpose and based on the data-mining techniques. The target users of the future reporting system-physicians, administrative staff, and patients-have been identified. Two major types of clinical reports have been found: predefined and customized. The decision of splitting reports into groups has been taken mainly because users were heterogeneous and had different access rights to the sensitive information. Data-mining process in the reporting system is based on descriptive statistics. It allows dynamically mined AssistMe databases and generates statistical reports about patient's morbidity, mortality, and comorbidity. Information is visualized in the chart way and can be also observed in tabular form. User interaction is also supported by the system.

A multimodal approach for reducing wound infections after sternotomy.

As previous efforts failed to reduce infection rates after cardiac surgery at our institution, we developed a concept based on adjustment of surgical technique. This concept was then evaluated in clinical practice. We modified our surgical technique towards: minimizing contamination, avoidance of devitalizing tissue, and securing a rigid fixation of the caudal part of sternum. After a pilot series sequential series was compared before and after introduction of the modified technique in a case-series design. All surgical site infections were recorded at discharge, after 6 weeks and by the attending cardiologist at 2 and 6 months. In the pilot series 9/136 patients developed sternal wound infections (SWI) compared with 15/89 patients in the control group (P=0.015). In the larger study population we found a significant drop in the total number of SWIs (72/772 vs 124/772, P<0.0001). Although not statistically significant a 32% reduction in deep SWIs was observed. No reduction in infections at harvest sites for graft material was seen. The preliminary results from the pilot study appear reproducible and we were able to reduce the incidence of SWIs significantly, using this simple modified surgical technique.

Risk factor analysis of Swedish Left Ventricular Assist Device (LVAD) patients.

BACKGROUND: The use of left ventricular assist devices (LVADs) is established as a bridge to heart transplantation. METHODS: All Swedish patients on the waiting list for heart transplantation, treated with LVAD since 1993 were retrospectively collected into a database and analyzed in regards to risk factors for mortality and morbidity. RESULTS: Fifty-nine patients (46 men) with a median age of 49 years (range, 14 to 69 years), Higgins score median of 9 (range, 3 to 15), EuroScore median of 10 (range, 5 to 17) were investigated. Dominating diagnoses were dilated cardiomyopathy in 61% (n = 36) and ischemic cardiomyopathy in 18.6% (n = 11). The patients were supported with LVAD for a median time of 99.5 days (range, 1 to 873 days). Forty-five (76%) patients received transplants, and 3 (5.1%) patients were weaned from the device. Eleven patients (18.6%) died during LVAD treatment. Risk factor analysis for mortality before heart transplantation showed significance for a high total amount of autologous blood transfusions (p < 0.001), days on mechanical ventilation postoperatively (p < 0.001), prolonged postoperative intensive care unit stay (p = 0.007), and high central venous pressure 24 hours postoperatively and at the final measurement (p = 0.03 and 0.01, respectively). Mortality with LVAD treatment was 18.6% (n = 11). High C-reactive protein (p = 0.001), low mean arterial pressure (p = 0.03), and high cardiac index (p = 0.03) preoperatively were risk factors for development of right ventricular failure during LVAD treatment. CONCLUSIONS: The Swedish experience with LVAD as a bridge to heart transplantation was retrospectively collected into a database. This included data from transplant and nontransplant centers. Figures of mortality and morbidity in the database were comparable to international experience. Specific risk factors were difficult to define retrospectively as a result of different protocols for follow-up among participating centers.