CARDIAC SURGICAL PROCEDURES.......

Cardiac surgical procedures

Cardiopulmonary bypass

Most of the cardiac operations rely on extra corporeal circulation to perfuse the body so that the heart is stopped for precise and accurate repair. Cannulation of aorta for arterial inflow and of the inferior venacava (IVC) and superior venacava (SVC) for venous drainage is the most common form of CPB. After the sternum has been opened, a longitudinal incision is made in the pericardium from the pericardial reflection at the aorta to the diaphragmatic portion of the pericardium. Two purse string sutures are inserted in the ascending aorta just below the great vessels. Aortic canula is inserted and tightened with tie to the purse string tourniquets. Commonly venous blood is drained from the right side of the heart via the SVC and the IVC, oxygenates and pumped back into the systemic circulation. The circulatory system is heparinised to avoid thrombus formation. Cardiotomy suction lines aspirate blood directly back to the pump where it is filtered, oxygenated and reinfused with the rest of the bypass volume into the arterial circulation.

After the CPB is established the heart is stopped by giving high potassium cardioplegia solution in to the aorta proximal to the aortic canula after aortic cross clamp. Systemic hypothermia is used during CPB to reduce the metabolic rate, and subsequently the energy demands of the organs. Cooling of the myocardium is achieved by using ice chilled Ringer Lactate or Normal Saline topically.

After the surgical repair has been completed, the surgeon prepares to discontinue bypass. Patient would have been rewarmed to normothermia and the heart will be contracting in a regular manner. The anaesthesiologist starts to ventilate the lungs and the surgeon occludes the venous line allowing blood to enter the right atrium (RA). When heart’s pumping action is judged to be sufficient and systemic blood pressures are stable, the venous line is clamped completely, and the heart resumes responsibility for maintaining the circulation. After bypass has been discontinued, and heparin reversal with protamine sulphate is begun, the CPB cannula is removed. Defibrillation by the internal application of a direct current (DC) electrical shock to the myocardium is instituted when the heart fibrillates.  

Coronary artery bypass graft (CABG)

CABG is done to bypass the blocked or diseased coronary arteries using the saphenous vein and the internal mammary artery and radial artery. This is done as beating heart surgery or using CPB machine.            

i. On pump CABG, we need to stop the patient’s heart and connect the patient to heart lung machine. This machine takes over the patients’ cardiac and pulmonary function and delivers oxygenated blood through out the body and brain while bypass is performed. 

ii.Off pump CABG (beating heart) eliminates the need for stopping the heart and use of CPB. It is mostly done for patients with lesions in the left anterior descending, diagonal and occasionally the right coronary arteries. Surgeon operates directly on the beating heart using Octopus, a coronary stabilizer placed around the target coronary artery, minimizes cardiac motion and allows the surgeon to perform the anastomosis.

            Endoscopic vein harvesting is a minimally invasive approach to saphenous veinharvesting.In this, 1-3 incisions are made on the leg and the vein is located under direct vision using a camera attached to the video externally. The remaining length of vein is excised via the video assistance with endoscopic scissors and clips. The benefit of using vasoview desection are small incision instead of vein length incision, less post operative pain, less scarring and less infection.

Cardiac ablation

This is done using epicor ultra cinch ablation device. This is performed in patients with AV reentry tachycardia (WPW syndrome). In cardiac ablation a radio frequency energy is rendered to inactivate the accessory pathway.

Valve surgeries

All valve surgeries are done after establishing CPB. The usual valve prostheses used are TTK chitra valve, St.Jude mechanical valve, Starr-Edwards mechanical valve, Medtronic valves and Perimount bioprosthetic valve.

i. Aortic valve replacement -Aorta is opened under CPB, diseased valve is removed and replaced with a prosthetic or bioprosthetic valve. The prosthetic valve is placed using non absorbable sutures.

ii. Mitral valve replacement-Diseased mitral valve is removed and replaced with artificial prosthetic or bioprosthetic valve. Single valve replacement and double valve replacement are usually performed here.

 iii. Valve repairs-Mitral valve reparative procedure is also being done because of the complications associated with prosthetic replacement and anticoagulation. Carpentier Edwards mitral and tricuspid rings (DE-VEGA suture annuloplasty) are used for annuloplasty.

Surgical repair of ASD is done under CPB

Tanned pericardial patch is used to close the defect.In sinus venosus defect, redirection of anomalous pulmonary venous return is also done. In ostium primum defect mitral valve cleft is sutured.

Vascular surgeries

Aneurysm repair

An aneurysm is the weakening of an artery. We usually deal with aortic aneurysms. Aortic aneurysms are named by the site where it occurs. An aortic root aneurysm, or aneurysm of sinus of Valsalva, appears on the sinuses of Valsalva or aortic root. Thoracic aortic aneurysms are found on the thoracic aorta; these are further classified as ascending, aortic arch, or descending aneurysms depending on the location on the thoracic aorta involved. Abdominal aortic aneurysms, the most common form of aortic aneurysm, are found on the abdominal aorta, and thoracoabdominal aortic aneurysms involve both the thoracic and abdominal aorta.

Surgical repair of the aneurysm depends on the location. Usually involves excision of the bulging section and replacing the weakened section of the vessel with a prosthetic graft. If the aneurysm is located in the ascending aorta just above the heart, the heart-lung machine will be used. In ascending aortic aneurysm with aortic valve involvement, a conduit is used to replace the diseased aorta and valve and the coronary arteries are stitched to the graft at separate openings (Bentall-De Bono procedure).

Embolectomy         

It is the rapid removal of emboli and thrombi from the vascular system. An embolectomy is the surgical removal of an embolus in a blood vessel and is done by using Fogarty’s embolectomy catheter.

Aortofemoral bypass graft

Peripheral artery bypass is the surgery to reroute the blood supply around a blocked artery in the legs mainly for chronic occlusions from atherosclerosis. The common procedures include aorto- femoral bypass and femoropopletial bypass using artificial grafts.

Carotid endarterectomy

 It is the surgery used to remove plaque from the carotid artery. During the operation, the surgeon peels off the plaque from the carotid artery. Once the plaque is removed from the carotid artery, the artery is repaired using saphenous vein. During the operation the blood flow to the brain is maintained using a special shunt (Pruitt-Inahara shunt).

Vascular access for hemodialysis

An arteriovenous fistula (A-V fistula) is made by joining an artery and a vein usually in the forearm (radial artery and vein). This is done for subjects who need long-term dialysis, and is done under local anesthesia.

We perform open heart, closed heart as well as thoracic and vascular surgeries. Open-heart surgeries are mostly done with the help of cardio pulmonary bypass (CPB) /heart lung machine. Beating heart surgeries are also being done here. Approach to open heart surgery is mainly through a median sternotomy incision, which provides excellent exposure for surgery of the heart and great vessels and facilitates canulation for a CPB.

THANKS FOR VISITING MY BLOG...KEEP IN TOUCH.