Step-by Step Heart Surgery
Unlike the rest of PM’s how-tos–catching a 1000-pound fish, building your own car, operating a backhoe–here’s one we hope you don’t get the chance to try out yourself (unless you take the medical school plunge and become a surgeon, of course). Heart surgeon Jai Raman walks us through the tools and steps of a successful heart surgery, and tells us how far the procedure has come in recent decades.
By Katherine LaGrave
Step 1: Sawing Through the Sternum
Anesthetic doses given for heart surgeries are standard for any major surgery–and have a component of analgesia, sedation and paralysis. All cardiac and respiratory parameters are carefully monitored and, once the patient is under, the surgeon gets out the saw.
The heart rests beneath the sternum–the organ’s skeletal armor and the central bone to which ribs are attached. Cracking this bone requires pressure, power and precision (but only about 30 seconds). The most common type of saw used in heart surgery is an oscillating saw, which moves up and down at a rapid speed and works like a jigsaw, enabling the fine blade to cut curved lines. Sometimes–especially on patients who have had heart procedures done before–surgeons will use a saw that’s like the one used to remove casts. It stops immediately when it senses tissue.
Surgeons cut the sternum either completely or partially, straight down the middle, but they don’t remove it. They then slowly spread apart the cut halves of the sternum with a retractor, something similar to a brace. This allows the entire chest and heart to be open before them.
Step 2: Working on the Heart
Becoming a cardiac surgeon means getting over a huge mental block: “You’ve got to get comfortable putting stitches into a beating heart,” Raman says.
The size and strength of stitches surgeons use to repair someone’s ticker can vary greatly depending on the procedure and part of the heart. When joining blood vessels–as in bypass surgery–doctors use sutures are made of polypropylene, a plastic polymer, and are as thin as a human hair. Doctors use magnifying surgical loupes when sewing this type of suture so they can see their stitching. Though these sutures are fine, they’re built to withstand pressure–suture companies have put them through controlled tests to simulate the pressure required to burst a vessel or disrupt tissue. When repairing or reconstructing heart muscle (like during a valve replacement), a heart surgeon uses thicker sutures.
Of course, some procedures require cutting, not just stitching tissues together. In a transplant, Raman will use an electrocautery, or diathermy, which cauterizes as it cuts and seals the small blood vessels, to cut through the pericardium, a sac that protects and contains the heart. He then removes the entire heart except for the back of the left atrium. When the heart is removed from the body, the patient is maintained on a heart-lung machine (also called a cardiopulmonary bypass machine), which oxygenates and circulates blood throughout the body, replacing the function of both the heart and the lungs. These machines are used in most cardiac surgical procedures, Raman says. The doctor will then trim the heart to fit snugly in the chest cavity and connect it to the left atrium again, specially tailoring each anastomosis–the joining of two blood vessels.
The amount of time required for a heart operation can vary wildly. What Raman calls a typical surgery–replacing an aortic valve–takes roughly 2 to 2-1/2 hours. But some that are a little more ambitious, like a heart transplant, require 7 to 8 hours.
Step 3: Putting the Sternum Back Together
Once the heart has been repaired, it’s time to put the sternum back together. But what about all those bony fragments? Fortunately, because heart surgeons break more bone than even orthopedic surgeons, repairing the sternum has been the focus of many surgical advances in the past few decades.
In the past, doctors used wire to repair the sternum, but this was problematic because bony fragments moved and did not remain aligned. Now surgeons use customized plates and screws to hold the breastbone and ribs in place as they heal. These, according to cardiothoracic surgeon Shahab Akhter of the University of Chicago Medical Center, provide better healing and lower risk of infection.
Step 4: Stitching Up the Skin
Gone are the days when stark black sutures were the mark of a surgery–surgeons now have a variety of options to employ. Akhter uses three layers to close the incisions. “No suture material is visible on or above the skin,” he says. “We use vicryl sutures for the first two layers and monocryl sutures for below the outside layer of the skin.” Both vicryl and monocryl sutures are absorbable and only used on soft tissue. Vicryl suturing typically holds strength for approximately two to three weeks and is fully absorbed within 60 days. Monocryl lasts longer, and is absorbed within 90 days. Open-heart surgery leaves a vertical scar on the skin over the sternum, and these scars are typically 7 to 10 inches long.
While new sutures, better breastbone plates and less invasive procedures are all marked advancements in the field, doctors aren’t stopping there. “The most important thing to realize is that we are trying our best to minimize the trauma to the chest to allow patients to recuperate from the surgery a lot faster,” Raman says. “[We’re] going away from the notion of having the whole heart exposed and doing a big cut down the middle. All that is being improved–and evolving–as we speak.”