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Open Heart Surgery
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Off Pump Coronary Artery Bypass surgery (OPCAB)
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Dr. Nachum Nesher
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Senior physician of Heart and Chest surgeries Department, The Tel-Aviv Sourasky Medical Center
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 Catheterization or bypass surgery? From time to time both doctors and patients ask themselves this question, which is in the center of scientific discussion more than 25 years.
Catheterization or bypass surgery? From time to time both doctors and patients ask themselves this question, which is in the center of scientific discussion more than 25 years.
There are two efficient approaches competing this issue, though being significantly different from each other and having both advantages and disadvantages that should be taken into account.
Recently, long-term advantage of surgical method has been increased not only in life quality improvement, but also in longevity.
Since the middle 1950s heart-lung machine usage has been applied that made it possible to carry out complicated heart surgeries on heart bleeding during the time that machine is executing heart and lungs function.
About 20 years after, the heart-lung machine became basic tool to perform coronary bypass surgeries. This machine includes a pump that directs blood flow according to heart output required (similar to a heart output of healthy person and is given to regulation) and oxygen that allows gases exchange instead of lungs activity.
Blood pouring and in vitro oxidation allow heart silencing and suturing of coronary bypasses under condition of stable surgery field and clean of blood.
In spite of significant technological improvements that were made in the pipeline and oxidant, within the last 50 years from first machine invention, patient’s connection to the heart-lung machine still hides a line of the following possible complications secondary to in vitro blood flow:
Strokes (mainly, embolic source), blood-clotting problems, kidneys insufficiency in different stages of severity and multi-systemic inflammatory reaction, thus a tendency of individual cognitive function damage after the surgery relatively to condition before the surgery.
Consequently, and in light of the described risks, bypasses without heart-lung machine usage on heart beating were already tested approximately 15 years ago.
These tests were anecdotal, especially for patients with increased surgery risk, but they were not comprehensively adopted, generally because of technique limitations, which caused sub-optimal anastomosis quality and prevented possibility of bypasses making in other heart areas.
In light of appropriate equipment development in the last decade and improvement of surgical skills, this method became acceptable and even leading at many centers around the world.
Bypass surgery on beating heart: during this bypass surgery on beating heart (OPCAB), heart continues to beat and does not connected to heart-lung machine at all.
This technique requires different stabilizers usage that settles working field and it is based on local pressure method and vacuum that affixes heart muscle only in close area to the general operated artery. And in such way makes it possible anastomosis performance in almost completely “isolated” from heart movement area.
Holding unit and located in critical places sutures allow heart moving upward and expose by this back and lower part of the heart for anastomosis performance in areas that were unreachable by old techniques.
In order to overcome coronary blood vessels bleeding during anastomosis performance, elastic suture is set in front of and behind of anastomosis point. This suture temporary “oppilates” blood vessels and makes it clean from blood anastomosis area.
This allows creating all required conditions for maximal accuracy of suturing. Heart muscle is able to survive from small damage in local blood supplying till the end of suturing.
This subject accumulated both professional and theoretical experience during last decade. Hundreds of Centers around the world operate on bypasses by using this method and its results are analyzed by number of the following indexes: anastomosis quality, achieved quantity of bypasses, if the surgeon operated on maximum required bypasses or compromised because of technique complications? Mortality and morbidity results as well.
Since the beginning of the results accumulation method, comparative works have been published and they confirmed that anastomosis quality of implants made without machine using the post surgery coronary catheterization is similar to those with heart-lung machine.
Immediate post surgery appreciation showed patency rate of 98.8%. Besides, patency rate that was measured about a year after surgery, showed similar result in these surgeries, as opposed to surgeries with heart-lung machine.
Advantages of surgery results. It was found a mortality diminution after OPCAB in number of comparative works in patients with increased surgery risk. There is a tendency for the rate diminution of neurological events after OPCAB surgeries compared to surgeries with heart-lung machine.
Consistent advantage was demonstrated also in easier damage to cognitive functioning after open-heart surgery. This improvement can be explained by diminishing of brain embolic events. Additional advantages include blood and its products return, artificial ventilation time reducing, reducing time of intensive care and general hospitalization.
Subjective reports indicate shorter recovery period duration and faster return to full functioning after these surgeries. It’s important to note that works that analyze subclinical indexes show a diminished release of heart enzymes after the surgery on beating heart by the side of surgery with heart-lung machine. This fact confirms better preservation of heart muscle and easier damage to it during the surgery.
There are important advantages of beating heart surgeries in groups with different risks in operated population. Morbidity is accompanied with high rate in advanced age.
There is a confirmation that surgery method without heart-lung machine is especially recommended for patients with sclerotic aorta, elderly people (75 and above), patients in short time after myocardial infarction, patients with weak heart function and kidney functioning disorder. Recently, diabetic population has been added and presented as an example that this method decreases a sub-surgical morbidity.
There are almost no disadvantages in this method. Surgical skills and long studying process lead to barrier (particularly psychological) many surgeons.
There are number of indications against (relatively) surgery performance on beating heart: the more blood vessels have smaller than ordinary diameter, the more technical difficulty appears in anastomosis performance and higher skills also required. Coronary arteries location in a heart muscle hardens surgery performance even in skilled arms.
Sometimes, there is no possibility to stabilize patient’s blood pressure during anastomosis performance (particularly on the back side of heart) and it makes necessary to consider a change to open technique with heart-lung machine usage. If consideration is right, there is only minimal risk in change from closed technique to open technique during the surgery.
Valve surgeries, bypasses and implants. Additional procedure performance as changing or correction constitutes indication against OPCAB surgery.
Likewise, there is a preference for arterial implants usage in order to perform bypasses also in surgeries on beating heart. This is because of belief (based on scholarly works) that the arterial implant’s quality better then venous ones for a long period of time.
Variety of possible use of arterial bypasses includes the left internal thoracic artery (LITA), the right internal thoracic artery (RITA), the radial artery that is reaped from a forearm, and the gastroepiploic artery that is taken from stomach wall.
In light of proven advantages of the two internal thoracic arteries usage, this method is the preferred one. During the period under discussion, 85% of anastomosis was performed with arterial implants.
Artery bypasses usage, particularly bilateral ITA, is an important factor in survival improvement and in repeated cardiac events prevention. This advantage even overpowers on basic advantage of bypass surgery, compared to angiographic procedures.
The only arterial implants use makes it possible to create implant’s ingredients that produce configuration, which prevents anastomosis necessity in aortas as noted above like an advantage, particularly in cases of hard calcification.
Implementation of these configurations during the surgery on beating heart allows resecularization with absolute prevention of the aorta touching (the untouched aorta surgery). This technique has an advantage of immediate morbidity diminution after the surgery, particularly a neurological morbidity.
Minimal surgery. Surgical advantage of the bypass surgery comes from its expression in MIDCAB type minimal surgery. This surgery is intended to chosen patients, which are appointed to bypass of the left anterior descending artery (LAD).
Instead of sternum bone lengthwise opening, it is possible to limit a surgical cut to minimal invasion between ribs, which are situated under the right nipple with limited length of six cm.
In addition to the absence of the heart-lung machine connection, there are advantages of this surgery in diminution of surgical trauma and prevention of morbidity connected to the sternum bone cutting.
One more possible implementation of this technique requires existing of the above-mentioned artery, LAD, which is the most important one in the aspect of life prolongation. According to this way, there are places where this bypass is being performed and then completed with catheterization procedure and stents placement in other less important arteries.
In recent years, more than 1,000 surgeries on beating heart have been performed at the Tel Aviv Medical Center. This is about 52% of total number of the bypass surgeries, among them about 900 OPCAB and 100 MIDCAB surgeries.
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