A Surgical Method for Subvalvular Structure Intervention Through a Transaortic Approach in Normal Bama Pigs

Summary

This study presents a surgical method for subvalvular aortic valve structure intervention using targeted tissue cutting via a transaortic approach in normal Bama pigs.

Abstract

Subvalvular structure abnormalities leading to left ventricular outflow tract (LVOT) alterations and myocardial hypertrophy are characteristic anatomical features of structural heart diseases such as hypertrophic cardiomyopathy (HCM). This study establishes a surgical method for aortic subvalvular structure intervention through a transaortic approach in normal Bama pigs. Animals were obtained from a certified experimental pig supplier in Beijing (Licence No. SCXK (Jing) 2018-0008).This method was validated in three healthy female Bama miniature pigs aged approximately 33-35 weeks, weighing 30-35 kg at the time of surgery. The procedure involves a median sternotomy and an anterior aortic wall incision, performed under cardiopulmonary bypass (CPB) support, hypothermic cardiac arrest, and direct visualization of the LVOT and subvalvular regions. Targeted tissue traction, localization, and cutting are utilized to remodel the subvalvular structure.

The complete surgical process includes anesthesia induction, placement of a central venous catheter and urinary catheter, surgical site disinfection and draping, median sternotomy, pericardial incision, and cardiac mobilization. CPB is established through right atrial drainage and retrograde coronary sinus perfusion. Following an anterior aortic wall incision, the left ventricle is accessed across the aortic valve, and subvalvular tissue intervention is performed under cardiac arrest. The procedure concludes with aortic closure, cardiac resumption of beating, CPB withdrawal, and thoracic closure. Throughout the procedure, hemodynamic stability was maintained, and the animal remained in good condition without intraoperative mortality. After surgery, the cut surfaces were smooth, and the surrounding structures remained intact.

This method demonstrates high reproducibility and procedural controllability, providing a stable surgical intervention model for studying subvalvular structure intervention. It also offers a technical platform for conducting histological analysis, surgical validation, and intervention strategy evaluation.

Introduction

Abnormalities in the subvalvular structures of the left ventricle play a crucial role in various cardiovascular diseases, particularly in patients with hypertrophic cardiomyopathy (HCM), where subvalvular anomalies contribute to left ventricular outflow tract (LVOT) obstruction and interventricular septal hypertrophy¹. These structural changes not only impair ventricular filling and ejection but may also lead to severe complications such as ventricular arrhythmias, sudden cardiac death, and chronic heart failure². Clinically, transaortic surgical resection of left ventricular tissues is often employed in such patients to....

Protocol

All animal procedures were approved by the Institutional Animal Care and Use Committee (IACUC) of Fuwai Hospital Chinese Academy of Medical Sciences, under approval number 0106-1-20-ZX(X)-21. All experiments were conducted in accordance with the ARRIVE guidelines and the National Institutes of Health Guide for the Care and Use of Laboratory Animals. Animals were housed under standard environmental conditions (temperature 20-26 °C, humidity 40-60%, 12 h light/dark cycle) with free access to food and water.

1. Experimental animal preparation

1. Obtain normal adult Bama miniature pigs from a certified experimenta....

Results

This surgical protocol enables stable exposure and controlled cutting of the subvalvular structures within the left ventricle. During the procedure, the aortic incision was accurately positioned, and entry through the aortic opening allowed clear visualization of the left ventricular outflow tract and the associated subvalvular region. The surgeon localized the cutting area by applying traction on the pre-placed suture and completed targeted subvalvular tissue cutting under direct vision using small, curved scissors. Pos.......

Discussion

Subvalvular structure abnormalities of the left ventricle represent critical anatomical changes in patients with hypertrophic cardiomyopathy (HCM), leading to impaired ventricular compliance, elevated diastolic pressure, and left ventricular outflow tract (LVOT) obstruction. These structural abnormalities constitute major pathological bases for clinical cardiac dysfunction and adverse outcomes^10,11 . In this study, we established a surgical method in normal Bama .......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
0.9% Sodium Chloride Injection	-	-	Used for irrigation and solution dilution
Anesthesia Machine	-	-	Delivers inhaled anesthetics and respiratory support
Anesthetics (Propofol, Fentanyl, Atracurium)	-	-	Used for anesthesia induction and maintenance
Aortic Retractor	SINOVIEW	RT37008-25	Used to retract the aorta and improve visibility
Atraumatic Forceps	SINOVIEW	FC22500-24	Used to grasp tissue while minimizing trauma
Cardioplegia Solution (St. Thomas)	-	-	Used for cardiac arrest and protection
Cardiopulmonary Bypass Machine and Tubing	-	-	Used for maintaining circulation during CPB
Central Venous Catheter Kit	-	-	Establishes central venous access
Endotracheal Intubation Set and Ventilator	-	-	Maintains airway during surgery
Flat Hook Retractor	SINOVIEW	RT37000-00	Used for tissue retraction in thoracic cavity
General Retractor	-	-	Used to retract tissue and expose surgical area
Hemostatic Forceps	-	-	Used to clamp blood vessels or tissue for hemostasis
Heparin Sodium Injection	-	-	Used for anticoagulation
IV Catheter·Radiopaque 22 GA × 1.00 in	BD Angiocath	381123	Used to establish venous access
Microsurgical Instrument Basket	SINOVIEW	90X0003	Used to store and transport microsurgical instruments
Minimally Invasive Curved Scissors	SINOVIEW	SC40230-25	Used in minimally invasive procedures for curved cutting
Minimally Invasive Double-joint Scissors	SINOVIEW	SC55001-29	Used for precise cutting in deep operative fields
Needle Holder	-	-	Used to hold suture needles during stitching
Scalpel Handle and Blade	-	-	Used to incise skin and tissues
Sterile Drapes, Sutures, Gloves, Masks	-	-	Used to maintain a sterile surgical field
Sterilization Box for Precision Instruments	SINOVIEW	90X0401	Used for cleaning and sterilizing surgical instruments
Tissue Forceps (Toothed/Non-toothed)	-	-	Used to grasp tissue
Tissue Scissors	SINOVIEW	SC35101-25SC	Used for general tissue cutting
Triple-joint Microforceps	SINOVIEW	FC17010-301	Used in microsurgery for delicate manipulation
Ultra-sharp Scissors	SINOVIEW	SC35101-23UC	Used for precise tissue dissection
Urinary Catheter and Drainage Bag	-	-	Used for urine drainage and monitoring
Vital Signs Monitor	-	-	Monitors ECG, blood pressure, SpO2, temperature