Surgical rescue mitral valve procedure post percutaneous transluminal mitral commissurotomy—a single-center observational study

Abstract

Percutaneous transluminal mitral commissurotomy (PTMC) has become the standard of care for severe mitral stenosis with favorable anatomy. Although the complications have reduced over the years, the need for emergency surgical rescue persists. This study evaluates the outcomes of surgical rescue performed within 24 h of undergoing PTMC from 1 January 2013 to 31 December 2019. Out of 2259 PTMC patients, 22 patients (< 1%) required rescue mitral valve surgery. Out of 22 patients, 17 patients (77.27%) developed mitral regurgitation; five patients (22.7%) had cardiac tamponade. Mitral valve replacement was performed in 20 patients (90.9%), while two patients (9.1%) underwent mitral valve repair. Cardiac tamponade was secondary to injury of the left atrium (9.1%), left ventricle (4.5%), and right ventricle (9.1%). Concomitant tricuspid valve repair was done in three patients (13.6%). Intraoperatively, anterior mitral leaflet tear was seen in 68.2% while posterior mitral leaflet tear was noted in 9.1%. Postoperatively, three patients (13.6%) required prolonged ventilation, incidence of stroke was 4.5% (n = 1), and in-hospital mortality was 4.5% (n = 1). Intra-aortic balloon pump was used in three patients (13.6%), preoperatively. We conclude that post-PTMC complications are rare, but they require urgent surgical intervention.

Introduction

Percutaneous transluminal mitral commissurotomy (PTMC) was first described by Inoue and colleagues as an alternative for surgical mitral commissurotomy in a case of severe mitral stenosis (MS) [1]. Over the last decade, PTMC has evolved into the first-line procedure for severe MS with acceptable anatomy. Previously, the incidence of severe mitral regurgitation (MR) post-PTMC was 6–7.5% [2], but recent data shows that the incidence has drastically reduced to 2.9% [3]. There is a dearth of information about the outcomes of surgical rescue for complications post-PTMC. Our study evaluates the outcomes of patients who underwent PTMC leading to complications requiring surgical rescue within 24 h.

Materials and methods

A total of 2259 patients underwent PTMC procedure during the period, out of which 22 patients (0.97%) had complications requiring surgical rescue within 24 h. Exclusion criteria for PTMC included the presence of other valvular pathology, atrial fibrillation (AF) with left atrial appendage (LAA) clot, moderate to severe MR, severe calcific mitral leaflets, and severe subvalvular involvement (Wilkins score more than 8). Patients who were stable enough to surgically intervene after 24 h were excluded from the study.

Aims

To study the outcomes of surgical rescue mitral valve intervention within 24 h of undergoing PTMC.

Primary objectives

To evaluate early mortality of patients undergoing rescue mitral valve procedure within 24 h of undergoing PTMC in our institute.

Secondary outcomes

This study also evaluates the clinical outcomes in terms of hospital stay, intensive care unit (ICU) stay, hours of ventilation, need for mechanical circulatory support, dialysis, permanent pacemaker, incidence of stroke, and low cardiac output syndrome.

Ethics and data collection

This study was approved by our institutional ethics committee (NHH/AEC-CL-2020–616). Data was collected retrospectively among the patients who required surgical rescue after PTMC. Baseline characteristics, preoperative data, reason for the need for surgical intervention, intraoperative findings, postoperative clinical outcomes, and complications were analyzed.

Definitions

Rescue mitral valve (MV) procedure: Surgical rescue after congenital catheterization procedure is defined as surgical intervention done within 1 week of the procedure to correct the complications [4]. We defined surgical rescue MV procedure as MV procedure done within 24 h of PTMC due to complications secondary to the procedure.

Prolonged ventilation is ventilatory support required for patients beyond 48 h.

Low cardiac output syndrome [5] was diagnosed based on the presence of two or more of the following findings: up trending or increased blood lactate level > 3 mmol/l (27 mg/dl), central venous oxygen saturation < 50%, urine output < 0.5 ml/kg/h, difference between peripheral skin and core body temperature > 7 °C, cardiac index of < 2.2 l/min/m².

PTMC procedure

PTMC was preferred for patients with severe MS and favorable anatomy, without LAA clots or other valvular lesions. Femoral venous access was obtained for the antegrade approach. The septal puncture was performed with a Brockenbrough needle and the MV was dilated serially with Inoue balloon under fluoroscopy guidance in a standard manner. Patients who developed sudden hemodynamic compromise were evaluated with a transthoracic echocardiography. Patients who developed pericardial tamponade were immediately drained by pigtail catheter under fluoroscopy guidance followed by surgical intervention. The procedure was immediately abandoned at the occurrence of acute severe MR and the patients were optimized either with inotropes or an intra-aortic balloon pump (IABP) followed by surgery.

Surgical procedure

All patients underwent surgical rescue through the median sternotomy approach. Cardiopulmonary bypass was established through aortic and bicaval cannulation. MV was exposed through left atriotomy along Waterston’s groove with the help of a self-retaining left atrial (LA) retractor. The rest of the procedure was performed in a routine standard manner.

Statistics

Categorical variables were described by taking percentages. Continuous variables were described as mean and variation of each observation from the mean value (standard deviation (SD)) represented as mean ± SD.

Results

The baseline characteristics are given in Table 1. Our study cohort was mostly a younger population with mean age of 37.45 years and predominantly female (86.4%). Closed mitral valvotomy was previously performed in three (13.6%) patients. In these patients, commissural fusion and progression of subvalvular disease was the reason for mitral restenosis. Out of 22 patients, 17 patients (77.27%) developed acute MR. Grade 4 MR was diagnosed in 14 patients (63.6%) and grade 3 in three patients (13.6%). This included the three patients who had undergone closed mitral valvotomy previously. Among the patients who developed acute MR, six patients (35.29%) developed acute pulmonary edema and 11 patients (64.70%) required preoperative ventilatory support.

Table 1.

Baseline characteristics

Baseline characteristics		N = 22
Age (mean ± SD)		37.45 ± 12.2
Body surface area (mean ± SD)		1.4 ± 0.16
Gender [n (%)]	Males	3 (13.6)
	Females	19 (86.4)
Hypertension [n (%)]		3 (13.6)
Diabetes [n (%)]		3 (13.6)
Previous closed mitral valvotomy [n (%)]		3 (13.6)
Previous PTMC [n (%)]		0 (0)
Preoperative rhythm [n (%)]	Atrial fibrillation	5 (22.7)
	Sinus	17 (77.3)
Preoperative transient ischemic attack/stroke [n (%)]		2 (9.1)
Preoperative ventilatory requirement [n (%)]		11 (50)
Preoperative ionotrope [n (%)]		4 (18.2)
Preoperative cardiac tamponade [n (%)]		5 (22.7)
Preoperative cardiac arrest [n (%)]		2 (9.1)
Preoperative acute pulmonary edema [n (%)]		6 (27.3)
Post PTMC mitral regurgitation grade [n (%)]	Grade 1	2 (9.1)
	Grade 2	2 (9.1)
	Grade 3	4 (18.2)
	Grade 4	14 (63.6)

PTMC, percutaneous transluminal mitral commissurotomy; n, number

Intraoperative details are given in Table 2. All patients underwent median sternotomy. Pericardial tamponade was diagnosed in five patients, which was drained along with the repair of the rent in the respective chamber followed by MV replacement/repair. Mitral valve replacement (MVR) was performed in 20 patients (90.9%) and repair was done in two patients (9.1%). MVR was performed with a bi-leaflet mechanical valve in 12 patients, while a tilting disc valve was used in eight patients. The MV repair technique used in both patients was open mitral valvotomy. Among the 17 patients who developed acute MR, anterior mitral leaflet (AML) tear was noted in 15 patients (88.23%), whereas posterior mitral leaflet (PML) tear was noted in two patients (11.76%). The concomitant tricuspid procedure was performed in three patients (13.6%). In one of the patient, delayed chest closure was performed in view of hemodynamic instability and the chest was closed the following day.

Table 2.

Intraoperative details

Intraoperative details		N = 22
Cardio pulmonary bypass time (min) (mean ± SD)		100.32 ± 34.25
Aortic cross clamp time (min) (mean ± SD)		65.5 ± 28.66
Mitral valve intervention [n (%)]	Replacement	20 (90.9)
	Repair	2 (9.1)
Intraoperative finding [n (%)]	Anterior mitral leaflet tear	15 (68.2)
	Posterior mitral leaflet tear	2 (9.1)
Cardiac tamponade [n (%)]	Left atrium rent	2 (9.1)
	Left ventricle rent	1 (4.5)
	Right ventricle rent	2 (9.1)
Concomitant procedure [n (%)]	Pulmonary vein isolation	2 (9.1)
	Tricuspid valve repair	3 (13.6)
Delayed chest closure [n (%)]		1 (4.5)

Postoperative details are given in Table 3. Prolonged ventilation was required in three patients (13.6%). Postoperatively, none of the patients required re-exploration, dialysis, or need for a permanent pacemaker. IABP support was provided preoperatively to stabilize three patients (13.6%). There was one in-hospital mortality (4.5%) due to stroke, low cardiac output syndrome.

Table 3.

Postoperative details

Postoperative details	N = 22
Prolonged ventilation [n (%)]	3 (13.6)
Bleeding requiring re-exploration [n (%)]	0 (0)
Permanent pacemaker implantation [n (%)]	0 (0)
Atrial fibrillation [n (%)]	3 (13.6%)
Stroke [n (%)]	1 (4.5)
Acute renal failure requiring hemodialysis [n (%)]	0 (0)
Sepsis [n (%)]	0 (0)
Low cardiac output [n (%)]	1 (4.5)
Intra-aortic balloon pump [n (%)]	3 (13.6)
In-hospital mortality [n (%)]	1 (4.5)

Discussion

PTMC has evolved into the first choice of non-pharmacological management for symptomatic severe rheumatic MS with favorable anatomy. Several scoring systems have been used all over the world for grading the lesion. In our institution, the Wilkins scoring system [6] is widely used which includes mitral leaflet thickening, calcification, mobility, and subvalvular apparatus. Studies have concluded that a Wilkins score of ≤ 8 is an independent predictor of reduced adverse events in terms of mortality, morbidity, and re-intervention [6]. Patients with concomitant valve lesions, LAA clots, severely calcific leaflets, and fused subvalvular apparatus were opted for surgical management.

In our study, the incidence of rescue intervention was lower (0.97%) compared to 2.2% by Varma et al. [7]. This was seen despite our definition of rescue extending over 24 h compared to only 6 h in the study by Varma et al. This could perhaps be related to technical improvement of percutaneous procedures over a period of time. The two causes of emergency surgery include acute mitral insufficiency and pericardial tamponade.

Acute MR

The most commonly involved mechanisms of acute MR following PTMC were AML tear, PML tear, commissural tear, and rupture of chordae tendineae [7, 8]. Kaul et al. [9] explained that leaflet rupture (72.7%) was the commonest cause followed by chordal rupture (18.2%) and commissural tear (9.1%). Severe MR requiring surgery was seen with leaflet tear and better outcomes were noticed with commissural tear. In contrast to the previous study, another study conducted by Sundaram et al. [10] using a Joseph mitral valvuloplasty (JOMIVA) balloon reported an incidence of 73.6% of severe MR due to commissural separation, 15.7% was due to leaflet tear, and 10.5% due to chordal rupture. Varma et al. [7] studied the incidence of acute severe MR requiring emergency MVR. The mechanism of lesion causing MR was mostly AML tear which involved the central portion in 43.5% of patients and para-commissural area in 43.5% of patients, followed by PML tear in 13%. Acar et al. [8] noticed that the majority of patients with MR had a tear in the para-commissural area, followed by the central portion of anterior/posterior leaflet and three patients had a chordal rupture. It was also noticed that one patient had papillary muscle rupture secondary to balloon dilatation. In our study, among the 17 patients who developed acute MR, only tear in AML and PML was noted. None of the patients had para-commissural, chordal, or papillary muscle rupture. We believe that the mechanism of these injuries is based on the extension of tears towards the pathway of least resistance. Since most of the patients were rheumatics, characterized by severe commissural fusion and severe subvalvular disease, the balloon dilatation pressure is transmitted to the least resistant part of the MV apparatus. The same concept applies to the patients who had undergone closed mitral valvotomy and presented with mitral restenosis due to commissural fusion.

Pericardial tamponade

A pigtail catheter was inserted under fluoroscopy guidance to relieve the tamponade followed by surgical repair of rent under cardiopulmonary bypass support. Injury to the chambers were mostly due to misplacement of the guide wire followed by sheath placement or balloon dilation. Varma et al. reported injury to left atrium in six cases, right atrium in one case, and perforation of left ventricle in one case [7]. This study also concluded that in patients with atrial enlargement undergoing PTMC, the correct placement of interatrial septal puncture is the crucial step in avoiding atrial wall injury. Evaluation of the position of septal puncture was beyond the scope of our study. Other studies have not mentioned the causes or reasons for pericardial tamponade.

Morbidity and mortality

Varma et al. [7] reported 9.6% operative mortality, 29% patients with incidence of low cardiac output, and one patient each requiring IABP and delayed sternal closure, while studies conducted in the early phase of PTMC evolution reported higher mortality of > 15% for surgical rescue MV surgery [11]. In our series, incidence of mortality and morbidity was comparatively low. This improvement in survival is attributable to the evolution of techniques in PTMC procedures and early intervention by surgical management. Patients developing acute MR require early mechanical ventilation or IABP support to reduce the insult to the ventricle which in turn reduces the incidence of low cardiac output in the immediate postoperative period, thereby reducing the mortality and morbidity. Mortality and morbidity were relatively high over the last few years; however, outcomes have improved in centers performing PTMC regularly with a cardiac surgical team backup to manage acute complications immediately.

Limitations

The major limitations of the study are the small sample size over a long-spanning study period and the retrospective nature of the study. This study includes only in-hospital outcomes of the post-PTMC surgical rescue MV procedure.

Conclusion

PTMC is the first line of management in rheumatic MS in selected patients with favorable anatomy. Even though complication rates are less, this procedure always needs a surgical backup unit. PTMC causing leaflet tearing requires immediate surgical intervention. We conclude that post-PTMC complications are rare, but they require urgent surgical intervention.

Author contribution

Ameya Kaskar and Venkatesa Kumar Anakaputhur Rajan were involved in writing the first draft of the manuscript. All co-authors helped in revising and approved the final draft of manuscript.

Funding

None.

Data availability

Data available on request from the corresponding author.

Declarations

Ethics approval

Approval was obtained from the ethics committee (Narayana Health Academic Ethics Committee) – letter no. NHH/AEC-CL-2020–616, dated 17 July 2021.

Statement of human and animal rights

The procedures used in the study adhere to the tenets of the Declaration of Helsinki.

Informed consent

Waiver of consent was approved by the institutional ethics committee (NHAEC).

Conflict of interest

The authors have no conflicts of interest to declare that are relevant to the content of this article.