Redefining Unilateral Pulmonary Edema after Mitral Valve Surgery on Chest X-ray Imaging Using the RALE Scoring System

Introduction: Unilateral pulmonary edema (UPE) is a potential complication after mitral valve surgery (MVS), and its cause is not yet fully understood. Definitions are inconsistent, and previous studies have reported wide variance in the incidence of UPE. This research aims at the evaluation of the Radiographic Assessment of Lung Edema (RALE) score concerning assessment of UPE after MVS in order to provide an accurate and consistent definition of this pathology. Methods and Results: Postoperative chest X-ray images of 676 patients after MVS (minimally invasive MVS, n = 434; conventional MVS, n = 242) were retrospectively analyzed concerning presence of UPE. UPE was diagnosed only after exclusion of other pathologies up until the eighth postoperative day. RALE values were calculated for each patient. ROC analysis was performed to assess diagnostic performance. UPE was diagnosed in 18 patients (2.8%). UPE occurred significantly more often in the MI-MVS group (p = 0.045; MI-MVS n = 15; C-MVS n = 3). Postoperative RALE values for the right hemithorax (Q1 + Q2) > 12 and the right-to-left RALE difference ((Q1 + Q2) - (Q3 + Q4)) > 13 provide a sensitivity of up to 100% and 94.4% and a specificity of up to 88.4% and 94.2% for UPE detection. Conclusion: The RALE score is a practical tool for assessment of chest X-ray images after MVS with regard to UPE and provides a clear definition of UPE. In addition, it enables objective comparability when assessing of the postoperative course. The given score thresholds provide a sensitivity and specificity of up to 94%. Further, UPE after MVS seems to be a rather rare pathology with an incidence of 2.6%.

Temporary venovenous extracorporeal membrane oxygenation after cardiopulmonary bypass in minimally invasive cardiac surgery via right minithoracotomy

OBJECTIVES

In minimally invasive cardiac surgery, it can be difficult at times to maintain adequate oxygenation with single-lung ventilation after weaning from cardiopulmonary bypass (CPB), and intermittent double-lung ventilation is required during hemostasis. Venovenous extracorporeal membrane oxygenation (VV-ECMO) after weaning from CPB eliminates the necessity of overinflation of the left lung and intermittent double-lung ventilation and enables secure and fast hemostasis. We investigated the effectiveness and safety of temporary VV-ECMO in MICS.

METHODS

Between May 2018 and March 2021, 149 patients underwent temporary VV-ECMO during minimally invasive cardiac surgery in our institutions. After weaning from CPB, the arterial circuit was reconnected to the right internal jugular venous cannula, the femoral venous cannula was pulled down by 20 cm, and VV-ECMO was established using the CPB machine and cannulas. After starting VV-ECMO, we administered protamine and performed hemostasis. Operative data and outcomes were retrospectively reviewed.

RESULTS

The mean VV-ECMO time and flow were 26 ± 13 minutes and 2.38 ± 0.40 L/m2, respectively. There was no thrombus in the CPB circuit, including the oxygenator. The trans-oxygenator pressure gradient index at the end of VV-ECMO significantly correlated with that at the start of VV-ECMO (r = 0.88; 95% CI, 0.79-0.94; P = .01). The 30-day mortality rate was 2.0%. The incidences of unilateral pulmonary edema, prolonged ventilation, and re-exploration for bleeding were 2.7%, 5.4%, and 2.0%, respectively.

CONCLUSIONS

Temporary VV-ECMO is safe and useful to maintain single-lung ventilation without overinflation after weaning from CPB for secure and fast hemostasis in minimally invasive cardiac surgery. No thrombotic event was found during temporary VV-ECMO without heparinization.

Unilateral pulmonary edema associated factors after minimally invasive mitral valve surgery

BACKGROUND AND OBJECTIVES

In recent years, minimally invasive cardiac surgery (MICS) has been developed and applied to a greater number of pathologies, especially in mitral valve surgeries, as it obtains results comparable to those of conventional techniques while entailing lower surgical trauma and shorter recovery time. MICS requiring one-lung ventilation has been associated to the appearance of unilateral pulmonary edema (UPE), which is a potentially serious complication. The objective is determining the incidence of UPE after mitral MICS and its development associated factors.

MATERIAL AND METHODS

Observational descriptive and single-center study analyzing data from patients undergoing mitral valve MICS (right mini-thoracotomy) consecutively collected between the years 2015 and 2017.

RESULTS

A total of 93 patients were included and 26 presented UPE. The most common complications after mitral valve MICS were atrial fibrillation (38.7%), UPE (28%) and transient and/or definitive second- or third-degree auriculoventricular block (19.4%). The UPE group had longer ICU stay (3.3 ± 8.0 vs. 1.84 ± 2.23 days) and longer total hospitalization length-of-stay (15.5 ± 34.7 vs. 10.6 ± 7.5 days). The mortality in the UPE group was 3.9%. A significant association was found between the following collected variables and the development of postoperative UPE: preoperative baseline pulse oximetry, preoperative use of ACE inhibitors, postoperative atrial fibrillation and 24 first-hours cumulative chest tube drainage volume on the first 24 h.

CONCLUSIONS

The incidence of UPE is high and its appearance is associated with a longer ICU and total length of stay. More studies are required to understand its pathophysiology and apply measures to help decreasing its appearance.

Unilateral Pulmonary Edema after Minimally Invasive Cardiac Surgery: A Case Report

Unilateral pulmonary edema after minimally invasive cardiac surgery is a rare, but potentially life-threatening condition. However, the exact causes of unilateral pulmonary edema remain unclear. We experienced aggressive unilateral pulmonary edema followed by redo-resection of recurrent left atrial myxoma through a right mini-thoracotomy. Intraoperative veno-venous extracorporeal membrane oxygenation was applied after the termination of cardiopulmonary bypass, and separate mechanical ventilation using a double-lumen endotracheal tube was applied after surgery. The patient was successfully treated and discharged uneventfully.

Unilateral pulmonary oedema after minimally invasive and robotically assisted mitral valve surgery

OBJECTIVES

Unilateral pulmonary oedema (UPO) is a severe complication of minimally invasive cardiac surgery. UPO rates and UPO-related mortality vary considerably between different studies. Due to lack of consistent diagnostic criteria for UPO, the aim of this study was to create a reproducible radiological classification for UPO. Also, risk factors for UPO after robotic and minimally invasive mitral valve operations were evaluated.

METHODS

Two hundred and thirty-one patients who underwent elective minimally invasive mitral valve surgery between January 2009 and March 2017 were evaluated. Chest radiographs of the first postoperative morning were categorized into 3 UPO grades based on the severity of radiological signs of pulmonary oedema described in this study. The radiographs were analysed by 2 independent radiologists and interobserver agreement was evaluated. The clinical significance of the classification was evaluated by comparing postoperative PaO2/FiO2 values and total ventilation times between the different UPO grades. Also, multivariable logistic regression analysis was employed to identify risk factors for UPO.

RESULTS

Interobserver agreement was substantial (Kappa = 0.780). Median total ventilation times were significantly longer with increasing severity of UPO, 15 (interquartile range 12-18) h for no UPO, 18 (interquartile range 15-24) h for grade I UPO and 25 (interquartile range 21-31) h for grade II UPO. Pulmonary hypertension [adjusted odds ratios (AOR) 2.51, 95% confidence intervals (CI) 1.43-4.40; P = 0.001], moderate or severe heart failure (AOR 2.88, 95% CI 1.27-6.53; P = 0.011), body mass index (AOR 1.14, 95% CI 1.02-1.28; P = 0.017) and cardiopulmonary bypass time (AOR 1.02, 95% CI 1.01-1.03; P < 0.001) were identified as independent risk factors for UPO and robotic approach (AOR 0.27, 95% CI 0.12-0.62; P = 0.002) as protective against UPO.

CONCLUSIONS

Due to the variability of the diagnostic criteria for UPO in previous studies, a radiological classification for UPO is required to reliably assess the rates and risk factors for UPO. The radiological classification described in this study demonstrated high interobserver agreement and correlated with total ventilation times and postoperative PaO2/FiO2 values.

Outcome of Unilateral Pulmonary Edema after Minimal-Invasive Mitral Valve Surgery: 10-Year Follow-Up

The study was approved by the institutional review board (IRB) at the University Medical Center Campus Kiel, Kiel, Germany (reference number: AZ D 559/18) and registered at the German Clinical Trials Register (reference number: DRKS00022222).

OBJECTIVE

Unilateral pulmonary edema (UPE) is a complication after minimally invasive mitral valve surgery (MIMVS). We analyzed the impact of this complication on the short- and long-term outcome over a 10-year period.

METHODS

We retrospectively observed 393 MIMVS patients between 01/2009 and 12/2019. The primary endpoint was a radiographically and clinically defined UPE within the first postoperative 24 h, secondary endpoints were 30-day and long-term mortality and the percentage of patients requiring ECLS. Risk factors for UPE incidence were evaluated by logistic regression, and risk factors for mortality in the follow-up period were assessed by Cox regression.

RESULTS

Median EuroSCORE II reached 0.98% in the complete MIMVS group. Combined 30-day and in-hospital mortality after MIMVS was 2.0% with a 95, 93 and 77% survival rate after 1, 3 and 10 years. Seventy-two (18.3%) of 393 patients developed a UPE 24 h after surgery. Six patients (8.3%) with UPE required an extracorporeal life-support system. Logistic regression analysis identified a higher creatinine level, a worse LV function, pulmonary hypertension, intraoperative transfusion and a longer aortic clamp time as predictors for UPE. Combined in hospital mortality and 30-day mortality was slightly but not significantly higher in the UPE group (4.2 vs. 1.6%; p = 0.17). Predictors for mortality during follow-up were age ≥ 70 years, impaired RVF, COPD, drainage loss ≥ 800 mL and length of ventilation ≥ 48 h. During a median follow-up of 4.6 years, comparable survival between UPE and non-UPE patients was seen in our analysis after 5 years (89 vs. 88%; p = 0.98).

CONCLUSIONS

In-hospital outcome with UPE after MIMVS was not significantly worse compared to non-UPE patients, and no differences were observed in the long-term follow-up. However, prolonged aortic clamp time, worse renal and left ventricular function, pulmonary hypertension and transfusion are associated with UPE.

Unilateral Pulmonary Edema After Robotically Assisted Mitral Valve Repair Requiring Veno-Venous Extracorporeal Membrane Oxygenation

Unilateral pulmonary edema (UPE) is an uncommon yet potentially life-threatening complication of minimally invasive cardiac surgery (MICS). Most frequently described after robotically assisted mitral valve (MV) repair, it is characterized by right lung edema, hypoxemia, hypercapnia, pulmonary hypertension, and hemodynamic instability beginning minutes-to-hours after separation from cardiopulmonary bypass (CPB). The authors describe a severe case with refractory hypoxemia requiring veno-venous (VV) extracorporeal membrane oxygenation (ECMO) after robotically assisted MV repair.

Minimally invasive mitral valve surgery

There is considerable interest and demand in the application of minimally invasive techniques in cardiac surgery driven by multiple factors including patient cosmesis and satisfaction, reduction of surgical trauma and the development of specialized instrumentation that allows these procedures to be performed safely. Minimally invasive mitral valve surgery (MIMVS) has been conducted for more than 25 years and has been shown to offer multiple benefits including better cosmetic results, enhanced post-operative recovery, improved patient satisfaction and most importantly, equivalent clinical outcomes with regards to quality and safety when compared to the standard sternotomy approach. MIMVS may be particularly beneficial in certain subgroups of patients, for example patients undergoing redo mitral valve surgery. In this article, we discuss patient selection criteria for MIMVS, the merits and drawbacks of MIMVS relative to conventional sternotomy approaches, and detail procedural aspects including anaesthetic management, intraoperative technique, and important considerations in myocardial protection and cardiopulmonary bypass (CPB). When considering developing a MIMVS programme, as for any new technique, a team approach to the introduction of the programme is essential. Although it is clear that patient selection is important, particularly early in a surgical programme, with experience complex repairs can be performed through a minimally invasive approach with excellent outcomes.

BISMICS consensus statement: implementing a safe minimally invasive mitral programme in the UK healthcare setting

Disseminating the practice of minimally invasive mitral surgery (mini-MVS) can be challenging, despite its original case reports a few decades ago. The penetration of this technology into clinical practice has been limited to centres of excellence, and mitral surgery in most general cardiothoracic centres remains to be conducted via sternotomy access as a first line. The process for the uptake of mini-MVS requires clearer guidance and standardisation for the processes involved in its implementation. In this statement, a consensus agreement is outlined that describes the benefits of mini-MVS, including reduced postoperative bleeding, reduced wound infection, enhanced recovery and patient satisfaction. Technical considerations require specific attention and can be introduced through simulation and/or use in conventional cases. Either endoballoon or aortic cross clamping is recommended, as well as femoral or central aortic cannulation, with the use of appropriate adjuncts and instruments. A coordinated team-based approach that encourages ownership of the programme by the team members is critical. A designated proctor is also recommended. The organisation of structured training and simulation, as well as planning the initial cases, is an important step to consider. The importance of pre-empting complications and dealing with adverse events is described, including re-exploration, conversion to sternotomy, unilateral pulmonary oedema and phrenic nerve injury. Accounting for both institutional and team considerations can effectively facilitate the introduction of a mini-MVS service. This involves simulation, team-based training, visits to specialist centres and involvement of a designated proctor to oversee the initial cases.

Robotic-assisted cardiac surgery without lung isolation utilizing single-lumen endotracheal tube intubation

OBJECTIVES

This study assessed the feasibility and outcomes of performing robotic cardiac surgery without lung isolation using single-lumen (SL) endotracheal tube intubation.

METHODS

Between 2013 and 2017, 132 patients underwent robotically-assisted atrial septal defect closure. A retrospective analysis was performed of 23 patients (11 males, mean age 30.9 ± 5 years) who underwent robotic surgery with double-lumen (DL) endotracheal tube intubation (group 1) compared with 109 patients (57 males, mean age 32.4 ± 7.5 years) undergoing the same procedure with SL endotracheal intubation (group 2). The patient groups were compared in terms of demographic characteristics, operative data, and complications. The technical feasibility of the robotic procedure without lung isolation was evaluated.

RESULTS

There were no mortality, intraoperative complication, and conversion. Mean total anesthesia time was significantly decreased in the SL intubation group (238.3 ± 22.4 vs 227.2 ± 21.2 minutes; P = .025). First-pass intubation success was significantly higher in the SL intubation group (17 [73.9%] vs 98 [89.9%] patients; P = .032). Mean ventilation time (10.9 ± 5.3 hours), intensive care unit stay (16.8 ± 10.1 hours), and the length of hospital stay (3.8 ± 1.2 days) was significantly decreased in patients with SL tube (P < .05). Unilateral reexpansion pulmonary edema was observed in five (21.7%) patients with DL tube, whereas no patient with SL tube had this complication.

CONCLUSIONS

SL endotracheal tube intubation without lung isolation is a feasible and safe airway alternative in robotic cardiac procedures. This approach resulted in shorter anesthesia time, ventilation time and the length of hospital stay. Port placement and robotic set-up can be uneventfully performed without lung isolation.

The successful use of extra-corporeal membrane oxygenation as rescue therapy for unilateral pulmonary edema following minimally invasive mitral valve surgery

Unilateral right pulmonary edema has been reported as a potential life-threatening complication after minimally invasive mitral valve surgery. Nearly 2% of these cases in the immediate postoperative period have been reported to require extra-corporeal membrane oxygenation support as a rescue therapy for severe hypoxia. The exact pathophysiology of this condition remains unclear, but has been assumed to be related to ischemia–reperfusion injury and re-expansion pulmonary edema. We present in this report the successful use of extra-corporeal membrane oxygenation to manage two cases of severe hypoxia and multiorgan dysfunction secondary to unilateral right pulmonary edema.

Robotic mitral valve replacements with bioprosthetic valves in 52 patients: experience from a tertiary referral hospital

OBJECTIVES

Robotic mitral valve replacement (MVR) emerged in the late 1990s as an alternative approach to conventional sternotomy. With the increased use of bioprosthetic valves worldwide and strong patient desire for minimally invasive procedures, the safety and feasibility of robotic MVRs with bioprosthetic valves require investigation.

METHODS

Between January 2013 and May 2017, 52 consecutive patients underwent robotic MVRs using the da Vinci Si surgical system (Intuitive Surgical Inc., Sunnyvale, CA, USA). Their mean age was 55.1 ± 13.8 years, and mean EuroSCORE II was 2.25% ± 1.25%. Among the enrolled patients, 32 (61.5%) patients presented with preoperative atrial fibrillation, 6 (11.5%) patients had experienced embolic stroke and 5 (9.6%) patients had undergone previous cardiac surgery. The operations were performed using cardiopulmonary bypass (CPB) under an arrested heart status.

RESULTS

Five porcine valves and 47 bovine valves were implanted. A total of 38 (73.1%) patients received concomitant cardiac procedures, including 26 Cox-maze IV procedures, 12 tricuspid valve repairs and 5 atrial septal defect repairs. The mean aortic cross-clamp and CPB times were 141.3 ± 34.3 min and 217.1 ± 42.0 min, respectively. There was no operative mortality. During the mean follow-up of 29 ± 15 months, no prosthesis degeneration was noted. The average left atrial dimension exhibited a significant decrease from 51.4 ± 11.5 mm to 42.6 ± 10.1 mm.

CONCLUSIONS

Robotic MVR with bioprosthetic valves is safe, feasible and reproducible. Mid-term results are encouraging. Both aortic cross-clamp and CPB times can be improved with experience.