Heart: An American Medical Odyssey (35 page)

In December 1799,
George Washington became ill with “inflammatory quinsy” (probably a peritonsillar abscess). When his pain became so severe that he could no longer swallow, eighty ounces (five pints) of blood was drained from Washington’s arm in a single day. That evening, the first president of the United States was dead. More than two centuries later, it is unclear whether General Washington died as a consequence of his likely bacterial throat infection or the well-intended but at best ineffective and probably harmfully exuberant, bloodletting.

Giorgio Baglivi, a seventeenth-century Italian who was physician to Popes Innocent XII and Clement XI, described the use of bloodletting for the pulmonary edema often encountered in heart failure. Although crude, bloodletting did improve the symptoms of congestive heart failure by decreasing the overall volume of blood in the body, and consequently, the amount of blood returning to the heart. This phlebotomy continued into the middle of the twentieth century and was then largely replaced by powerful diuretic medications that harnessed the kidneys” natural ability to remove fluid from the body. When I was a medical resident in New York in the late 1980s, I struggled one night to keep a patient with advanced heart failure alive. Having exhausted
all the options I knew, I called the patient’s attending to apprise him of the grim situation and to ask if he had any suggestions.

“Take off five hundred cc of blood,” he said.

Skeptical of the quaint approach but knowing that there was nothing to lose, I followed the senior physician’s recommendation, removing half a liter of blood. I was surprised, and humbled when the patient rallied.

•  •  •

Although both sides of the heart can “fail,” impairment of the contractile function of the left ventricle is more common and may occur as a consequence of prior heart attacks, valvular disease, viral infections of the heart, toxins like alcohol, certain types of chemotherapy, or unknown (“idiopathic’) causes. When the right ventricle fails, it is most commonly the result of failure of the left ventricle: the blood that backs up into the lungs increases the pressure in the pulmonary vessels, which strains the usually thinner-walled, less muscular right ventricle.

As the left ventricle becomes progressively impaired, it compensates by dilating (getting larger and holding more blood) and beating faster. Over time, its ability to compensate declines, and the patient increasingly develops the symptoms of heart failure, such as fatigue and shortness of breath; toward the end, organs shut down. Right ventricular failure, by contrast, typically presents as swelling in the legs and abdomen, caused by the backup of the blood that would normally be returning to the heart.

As a heart begins to fail, the body responds by activating several compensatory mechanisms resulting in the elaboration of hormones that increase salt and water retention, constrict blood vessels, and increase the heart’s contractile force and rate. These responses turn out to be very helpful if the drop in cardiac output is the result of an acute process like bleeding, but they become counterproductive over time if the cardiac output has declined because of an intrinsic problem with the heart. The concept that the physiological response to declining heart function might be “maladaptive” was developed in the 1980s and led
to the use of vasodilators and beta blockers for patients with heart failure.

Vasodilators, which include angiotensin II–converting enzyme (ACE) inhibitors like lisinopril or enalapril, are drugs that dilate blood vessels and reduce resistance to cardiac emptying, making it easier for the heart to eject blood, increase cardiac output, and help prevent the heart from dilating. Clinical trials in the late 1980s proved that ACE inhibitors improve the survival of patients with heart failure, and ACE inhibitors and other related vasodilators have become a standard component of therapy for congestive heart failure.

Beta blockers (metoprolol, carvedilol, and others) are drugs that attach to sites on myocardial cells (beta receptors) that normally bind epinephrine and norepinephrine, adrenaline-like hormones that stimulate the heart in the “fight-or-flight” response, and are also elaborated in heart failure. Although it is somewhat counterintuitive, the beta blockers (which are cardioinhibitory) have been shown to decrease mortality and increase the cardiac output in patients with impaired ventricular function.

•  •  •

In April 2010, Liz Cheney called and asked if I had a few minutes to talk. I had been driving home through the mountains of western Maryland, and despite my GPS, I was a little lost, so I pulled over.

“My dad is dying,” Liz said plainly.

The vice president had clearly deteriorated over the past few months, and although at the moment he appeared quasi-stable, there was no question where his trajectory was heading. The heart attack in February, although small, had taken muscle Mr. Cheney couldn’t spare, and he was requiring higher doses and more frequent adjustments of multiple medications to keep him out of heart failure.

“Is it true that there isn’t anything else that can be done for him?” Liz asked, not waiting for me to respond to her first statement. I had gotten to know Liz fairly well over the prior decade and spoke with her occasionally, usually when there was an issue related to her father’s care
that needed clarification. Although I didn’t know it at the time, she was calling because her father had taken her aside to tell her that he thought the end was near and that she needed to accept it.

“No, that’s not right,” I said. I explained to her that six months earlier, I had told the vice president that should the circumstances warrant, he could be eligible for a mechanical ventricular assist device and even potentially a heart transplant.

“He’s not too old for that?” she asked.

I reassured her that he was not. Although the assessment of the severity of her father’s illness was correct, I thought he definitely still had options.

•  •  •

Heart failure kills more than fifty-six thousand Americans every year, about the same as breast cancer. Although people with heart failure live longer and better than in the past, 50 percent of people with a new diagnosis of heart failure will be dead within five years. Acknowledging the need for better options for patients with end-stage heart disease, in 1964
the federal government began funding a program intended to spur the development of mechanical cardiac assist devices, eventually investing over $400 million in the technology.

One of the early proponents of this initiative was Dr. Michael DeBakey, the legendary Houston heart surgeon and prolific innovator whose contributions to cardiac and vascular surgery spanned three-quarters of a century. In 1932, at the age of twenty-three, while still a medical student, Dr. DeBakey invented the “roller pump,” which was used for decades to transfuse blood and later became a central component of the heart-lung machines created by Dr. John Gibbon and others.
Dr. DeBakey developed surgical techniques to repair aortic aneurysms and carotid artery blockages, introduced Dacron as a material for synthetic vascular grafts, invented over fifty surgical instruments, and helped to create the concept for the mobile army surgical hospital (MASH) unit. He was said to have performed over sixty thousand heart operations during his extraordinary life and claimed to have accomplished the world’s
first coronary bypass graft operation in 1964. At the time of his death in 2008 at age ninety-nine, the
New York Times
fittingly described Dr. DeBakey as a “rebuilder of hearts.”

In the early 1960s Dr. DeBakey and his team created several pumps intended to temporarily support or even replace the function of an ailing heart. In David K. C. Cooper’s book
Open Heart: The Radical Surgeons Who Revolutionized Medicine
, Dr. DeBakey described his rationale for developing these ventricular assist devices (VADs):

We became interested in the artificial heart as an extension of the heart-lung machine. As we developed more experience with the heart-lung machine, my feeling was that there were high-risk patients who would only be able to be weaned from the machine if we continued using it for, say, several hours. My reasoning was that if you could support them for a longer period of time, perhaps the heart might recover.

The heart is really composed of two pumps. The pump on the right side (the right ventricle) receives returning venous blood from the body and propels it into the lungs, where oxygen is swapped for carbon dioxide. The oxygenated blood then returns to the left side of the heart, where the thicker and more muscular left ventricle thrusts it back into the body at much higher pressure. Theoretically a mechanical device could replace the function of the left ventricle (left ventricular assist), the right ventricle (right ventricular assist), or the whole heart (total artificial heart).

The earliest designs for these systems were relatively crude and were constantly refined as animal research and clinical experience progressed. In a review article written nearly forty years after the fact, Dr. DeBakey described the first successful implant of a left ventricular assist device (LVAD):

Our first clinical application of this pump was on August 8, 1966, in a white woman with heart failure caused by severe aortic insufficiency
and mitral stenosis. After replacement of both valves, it was impossible to wean the patient off the heart-lung machine despite prolonged support, and the bypass pump was then attached to the patient. With a pump flow of 1,200 mL/min, it was possible to wean the patient off the heart-lung machine. On the 10th postoperative day, it became possible to discontinue the use of the bypass pump as the heart maintained normal function. The patient recovered completely and returned home to resume normal activities. Unfortunately, she was killed in an automobile accident 6 years after the operation.

On April 4, 1969, Haskell Karp, a forty-seven-year-old man with congestive heart failure awaiting transplant, was taken to the operating room at St. Luke’s Hospital in Houston for a procedure scheduled as a surgical excision of a thinned and infarcted segment of his left ventricular wall. The procedure that was ultimately performed would make history and also engender a nearly forty-year feud between two of the world’s greatest heart surgeons.

Mr. Karp’s surgeon was Dr. Denton Cooley, who years earlier had been recruited to Houston by Dr. DeBakey (and three decades later would be asked by the Bush campaign to vet the health of Dick Cheney). In Cooper’s book, Dr. Cooley recounts the events surrounding that operation:

In 1968, it was evident to me that it was time to try the artificial heart. We were having a number of frustrations in watching people die who could have been saved with a heart transplant. One of my colleagues was a fellow by the name of Dr. Domingo Liotta, who had spent time trying to develop an artificial heart. He came to me rather frustrated, saying DeBakey was apparently not interested in going forward with its clinical application. . . . I knew that if I went to Dr. DeBakey to get permission from our department of surgery, we would get only delay and further negative response. So I decided that the time had come to take a bold step. The opportunity arose
to go ahead and do it, and suffer any repercussions that might follow. We did just that.

We had the ideal candidate who was dying and needed a cardiac transplant, a gentleman named Haskell Karp. We were just interested in seeing if you could sustain a human life with an artificial device. Sure enough, that proved to be the case. The patient did very well with the artificial heart, but unfortunately he died following his transplant because of an infection. I have no regrets for having taken that step.

Dr. DeBakey later countered that since the device could not keep an animal alive for a prolonged period of time, he would not use it in a human. Dr. Cooley’s brash implant of the unapproved, and unproven, total artificial heart led to a schism with Dr. DeBakey that continued for nearly four decades. The surgical legends reconciled just months before DeBakey’s death.

•  •  •

Over the past two decades, mechanical cardiac assist devices have become the real “time machines,” giving patients struggling after cardiac surgery time to recover (“bridge to recovery’), patients on the transplant list the endurance to survive until a donor organ is located (“bridge to transplant’), and an option for patients with advanced heart failure who are ineligible for an organ transplant and have historically had no options (“destination therapy’).

The initial VADs created pulsatile flow, mimicking the heart’s rhythmic movement of blood, and were driven pneumatically by compressed gas delivered through drivelines mated to a large external console. Later iterations of the technology incorporated electrically powered pumps that could be run from battery packs, offering patients more freedom. Although these systems greatly increased the survival rate of patients waiting for transplants, the pumps were relatively large and prone to mechanical failure.

Newer-generation VADs have moved to a different technology and incorporate
a rapidly spinning internal rotor to create a continuous (nonpulsatile) output of blood. Compared to their forerunners, these continuous-flow VADs have far fewer internal moving parts (which increases their reliability and durability), need less anticoagulation therapy, are much smaller, and can run for many hours on easy-to-carry external batteries.

•  •  •

In mid-June 2010, Vice President Cheney redeveloped atrial fibrillation and fluid retention, necessitating the reluctant reinstitution of blood thinners to protect him from a stroke and also a big slug of diuretics to clear the fluid. As is typical for a patient with severe heart failure, it was becoming increasingly difficult to keep him in any semblance of clinical balance.

Dick Cheney had done well for many years, but in less than eighteen months, he had morphed from one of the most powerful men in the world to the sickest patient in my practice, someone requiring nearly constant medical attention. Clearly we were reaching the limits of contemporary medical therapy. If Cheney was going to survive beyond the next few months, he was going to need a VAD. I had broached the topic with the vice president the previous fall, but at that time he was still relatively well and the conversation was brief and maybe a bit premature. Now he was really sick, and it was starting to look as if we may have waited too long.