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. 2001;28(2):133–138.

A Biographical Sketch of Lewis Dexter

Madhuri Mukhopadhyay 1
PMCID: PMC101154  PMID: 11453126

Abstract

Dr. Lewis Dexter was an outstanding cardiovascular physiologist and clinician, a respected teacher and scientist, and, most importantly, a fine human being. During his life, he brought the cardiac catheter from the laboratory to the patient and trained several generations of cardiologists. Dexter's laboratory was the first to elucidate the pathophysiologic alterations present in many forms of congenital heart disease, including atrial septal defects, patent ductus arteriosus, tetralogy of Fallot, ventricular septal defects, and pulmonic stenosis. Subsequent work in Dexter's laboratory led to the 1st measurements of pulmonary capillary wedge pressure and to the precise calculation of stenotic valve areas from hemodynamic parameters measured during cardiac catheterization.

During a teaching exercise, Dexter demonstrated that exercise with a cardiac catheter in the heart was safe and produced clinically important data, by having a cardiac catheter inserted in himself. Over the years, many significant pathophysiologic studies that explored pulmonary embolism, valvular heart disease, right and left ventricular function, and pulmonary hypertension were published from Dexter's laboratory. But Lewis Dexter was more than a brilliant researcher. “Lew” was very close to his fellows and students, whom he considered extensions of his family. Dexter was a remarkable teacher, a compassionate physician, and a scrupulously honest investigator. Dr. Lewis Dexter had a major impact on modern medicine and was one of the great cardiologists of the 20th century.

Key words: Heart catheterization/history/instrumentation; heart defects, congenital/therapy; history of medicine, 20th cent.; pulmonary wedge pressure

Where is my mitral man?” Dr. Lewis Dexter asked a group of 40 eager, young medical doctors and students. He singled out a 1st-year student, Hasan Garan, standing farthest from the patient's bedside. Dexter (Fig. 1) remembered that this student had expressed a desire to improve his skills in listening to heart murmurs. So he grabbed the student by the arm, handed him the stethoscope, and said, “Listen to this rumble; we're not going anywhere until you hear this rumble!”* This is just 1 example of Dexter's love for knowledge and the sharing of that knowledge with his students. Many medical students at Harvard Medical School and, after his official retirement, at the University of Massachusetts Medical School, had the privilege of studying with Dexter.

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Fig. 1 Copy of the portrait of Dr. Dexter in the amphitheater of the Brigham and Women's Hospital in Boston. The dedication is to Dr. R.C. Schlant.

(Photo courtesy of Dr. Joseph S. Alpert; Tucson, Arizona)

Although I did not have the opportunity to meet or talk with Dr. Dexter, I have spoken with many of his students and with members of his family, who in turn have taught me a great deal about Dr. Dexter and his enthusiasm for life. It is clear that he loved his family, and he often included his fellows and other students in family activities. He loved science, he loved practicing medicine, and he loved sailing. Because he demonstrated the highest standards of respect, integrity, compassion, dedication, open-mindedness, honesty, and humility, Dr. Dexter represented an ideal that many of his students aspired to achieve. Those who were fortunate enough to be his students will never forget his guidance.

Student of Soma Weiss and Bernardo Houssay

Lewis Dexter was born and reared in Concord, Massachusetts. His father was an Episcopal priest who served congregations in New Bedford and Concord. Dexter completed his secondary schooling at Concord High School and The Choate School. After graduating cum laude from both Harvard College (1932) and Harvard Medical School (1936), he fulfilled a 2-year residency at Presbyterian Hospital in New York. He then returned to Boston and studied as a fellow with Dr. Soma Weiss at Boston City Hospital. Together, they wrote a book on the toxemia of pregnancy, 1 along with several articles. 2,3

In 1940, after 2 years with Dr. Weiss, Dexter went to Buenos Aires to study with Dr. Bernardo A. Houssay, who later received the 1947 Nobel Prize in Medicine (Physiology) for his discovery of the role of the pituitary gland in regulating glucose homeostasis. In Houssay's laboratory, Dexter studied hypertension. 4,5 Upon his return to Boston in 1941, Dexter continued his research under the direction of Weiss, at Peter Bent Brigham Hospital, where he focused his studies on the hormone renin and its association with hypertension. After Weiss's untimely death, Dexter remained in the same laboratory and continued his investigations on renin. Still a young clinical investigator, Dexter was soon appointed as a full-time faculty member at the Peter Bent Brigham Hospital. It was during this time that he met and married Cassandra (“Sandy”) Kinsman. 6,7

Husband and Father

Sandy Dexter was a constant support to her husband until his death at the age of 85. During our interview, she spoke with fond memories of the parties that she and her husband had hosted at their home, recalling that they had a 1-bedroom apartment with a small living room, which they had converted into a study. “We would invite a group of 8 or 10 students to our home, and since we didn't have any furniture at the time, we would all sit on the floor. Lew would then teach physical diagnosis to the students. We held these parties about 5 times a year.”* Although the Dexters had 3 children of their own, Dr. Dexter considered his fellows to be his extended family. Mrs. Dexter also described summer lobster cookouts and trips on their boat (Fig. 2). “We had a 38-foot yawl, with 2 masts, 3 sails, and a generous cockpit. We would take 10 to 14 fellows down to Westport Point. The boat would be crawling with them!”* Sandy Dexter's warmth and generosity made these informal gatherings possible. Clearly, her unfailing love and support had a positive influence on Dr. Dexter, both personally and professionally.

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Fig. 2 Lew and Sandy Dexter at the helm.

(Photo courtesy of Dr. Joseph S. Alpert; Tucson, Arizona)

Scientist Dedicated to Research

Cardiac Catheterization.

In the course of his renin studies, Dr. Dexter performed one of the 1st cardiac catheterizations on a human being. On 7 December 1944, he was catheterizing the renal vein of a hypertensive patient and decided to explore a little farther. He later recalled,

… I decided to wander around the heart which I understood was above the diaphragm somewhere. Suddenly, this catheter came clear out in the lung field and I was sure I [had] perforated the heart. I didn't have any idea of what to do and … I turned on the overhead lights and said, “Mr. S____, how are you?” He said, “I feel a hell of a lot better than you look.” Then I was pretty sure that, having perforated the heart, it just sort of sealed itself off and [I] wondered what would happen when I pulled it back. So I closed my eyes and then I pulled the catheter back and nothing happened. And then … it was all over and I put my little Bandaid on his wound and I went and looked up the anatomy of the chest and I figured I had gone into the pulmonary artery. 8

Later that day, Dexter discussed his adventure with Dr. C. Sidney Burwell, the dean of the Harvard Medical School at that time. Burwell remarked that if Dexter could get to the pulmonary artery again, then he would be able to study congenital heart diseases. On the basis of this experience, Dexter decided to change his focus of study from hypertension to the heart. 6–10

Dexter began to methodically investigate the pathophysiology of congenital heart disease. He was the first to use cardiac catheterization to diagnose tetralogy of Fallot, atrial septal defects, and ventricular septal defects, by measuring intracardiac pressures and blood saturations. His persistence, meticulous observations, and careful records resulted in the publication of a series of articles that described the proper techniques for quantifying left-to-right shunts and bidirectional shunts, as well as the pathophysiology and natural history of atrial septal defects. 11–16 These developments in diagnostic cardiac catheterization led to many surgical advances, including techniques to correct most of the common forms of congenital heart disease. 6–10

Pulmonary Capillary Wedge Pressure.

Dexter's pioneering work did not stop there. His interests in rheumatic fever reiterated the value of diagnostic cardiac catheterization, which he used for the accurate diagnosis of valvular heart disease. Dexter was the 1st person to place a cardiac catheter into the pulmonary artery “wedge” position, which led to the discovery that pulmonary capillary wedge pressure is the same as left atrial pressure and left ventricular filling pressure (in the absence of mitral stenosis). 17,18 Today, the hemodynamic management of patients in the intensive care unit would be impossible without knowledge of the pulmonary capillary pressure. 19

The Gorlin Formula.

At about the same time that Dexter discovered the significance of the pulmonary capillary wedge pressure, Dr. Richard Gorlin (one of Dexter's fellows) and Gorlin's father (an engineer) developed the formula for calculating valve areas from the ratio of flow and pressure across the orifice. Although Dexter played a major role in producing this classic paper, 20 he requested that it be submitted without his name so that the Gorlins would receive sole credit for this important contribution. 6,7 The use of the well-known Gorlin formula established precise indications for the surgical correction of valvular diseases.

Dexter conducted research on many other topics as well. The pathophysiology of pulmonary hypertension and pulmonary embolism was defined in his laboratory. 21,22 He was also the 1st scientist to personally demonstrate that exercise with a cardiac catheter was safe and produced clinically significant results. One of Dexter's fellows, Dr. Virendra Mathur, recalled,

[Dr. Dexter] did not believe that he should subject anybody to a procedure that he himself would not be willing to undergo. He asked one of his fellows to place a catheter in his [Dexter's] pulmonary artery. Once the catheter was in, Dr. Dexter gently sat up, and then very gently dangled his feet. Everyone was watching and everyone was frightened. Was he going to have a cardiac arrest? (Remember, this was before the invention of defibrillators.) And then he stood up. Of course, nothing happened to him. Then he started to skip a little, and then proceeded to do vigorous exercise. He promptly recorded all the responses to vigorous exercise before removing the catheter. He was willing to subject himself to the first-ever exercise carried out with a catheter in the heart.*

Dr. Dexter's commitment to research, along with his daring teaching techniques, created a lasting impression in the minds of all his fellows.

Mentor and Friend

Lewis Dexter was affectionately called “Lew” by his friends, many of whom were his students and colleagues. According to one of his students, Dr. Joseph Alpert (Fig. 3), “Lew Dexter was a stickler for careful, meticulous observation and repeated experiments to be sure that we had not ‘fortuitously’ gotten a certain result. He was one of the first to be an advocate for evidence-based medicine.”**

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Fig. 3 Dr. Lew Dexter with his fellows, Dr. Joseph Alpert (left) and Dr. James Dalen, 1972.

(Photo courtesy of Dr. Joseph S. Alpert; Tucson, Arizona.)

Dr. Paul Stein recalled Dexter's tenacity and dedication to truth through the highest standards of research:

He loved his research and insisted upon absolute intellectual honesty. There was no room for the slightest exaggeration. Everything had to be exactly and precisely accurate; there was no room for slovenliness. He taught us how to do things on our own…. “If you want to do it, then do it!” He taught us independence. He gave us plenty of freedom, and supervised us to let us know if we were doing something wrong.*

Stein also remembered Dexter's fatherly attitude toward his fellows and his commitment to maintaining contact with them.* Dr. Mathur remarked, “He was always sending handwritten holiday greetings, even after 30 years of separation. He kept a picture of his previous fellows, which he lovingly called ‘The Rogues’ Gallery.'”**

Dr. William Grossman was another of Dexter's students. During his 1st-year fellowship with Dr. Dexter, Grossman's father died. Grossman recalled that Dexter pulled him aside and shared his memories of his own father for about 2 hours. 9,***

A Patient Himself

The loyalty of his fellows became most apparent in 1978, when Dr. Dexter was admitted to the hospital after several weeks of progressively worsening angina. A number of tests were performed, and serial electrocardiography suggested that Dexter might have a narrowed left main coronary artery. (In those days, angiography was not generally performed in patients with acute coronary conditions.) Dr. Dexter documented the incident in a chapter titled “Cardiac Arrest,” 23 wherein he described the “luck” he encountered the day he was admitted to the hospital.

The first fortuitous event for me was that as I lay in the Coronary Care Unit talking with the chief of the unit, my eyes rolled up and I became unconscious…. If any of you who are reading this decide to have a coronary occlusion, please arrange to have it in a coronary care unit. The doctors and nurses promptly discovered that I had electromechanical dissociation, often considered to be a good reason for discontinuing CPR. The second fortuitous event was that since I had trained, directly and indirectly, most of the physicians in attendance, they were reluctant to discontinue CPR until (third fortuitous event) the cardiac surgeon came to see me. No one expected him to be willing to operate because there were no coronary angiograms. To everyone's amazement, he said “Let's operate.” CPR was given continuously for about 40 minutes during the time of transfer from the Coronary Care Unit in elevators and along corridors to the OR.

The fourth fortuitous event was that in the OR, a surgical team and an extracorporeal pump team were awaiting the arrival of another patient for coronary bypass surgery. The teams were scrubbed and the pump was all prepared. The other patient's operation was postponed, and I was slipped into his place. Thus, there was no delay and I was put on bypass in five minutes. This, together with expert CPR, has resulted in my still having a brain. 23

Dr. Grossman recalls that day vividly, because he helped operate on Dexter. After the surgery was over and Dexter had regained full consciousness, he spoke with his surgeons. Among his 1st postoperative words were, “This was completely unethical. You did it without my informed consent!” 9,23,*** These comments, though in jest, clearly showed Dexter's tremendous respect for the patient. In turn, patients responded to him with a sense of trust. 24,*** Dr. Garan (whom Dexter affectionately called his “mitral man”) remembered Dr. Dexter's tremendous gift for communication with his patients:

The greatest experience in all those months [of 1st-year medical training] was to see Dr. Dexter at the bedside, where he was an unbelievable master. He would get to the patients and, in absolutely no time, figure out the patients' concerns and put them at ease. If they were feeling anxious, that would be immediately addressed. He would relieve their fears and anxieties, and the patients would listen.****

A Humble Man of Medical Distinction

Dexter was a member of the Association of American Physicians, American College of Physicians, American Heart Association, American College of Cardiology, American Academy of Arts and Sciences, Association of University Cardiologists, American Clinical and Climatological Association, and the British, Mexican, Peruvian, and Argentine cardiac societies. 24

Dexter published more than 200 peer-reviewed scientific papers during his career. 7 Dr. Heinrich Taegtmeyer, a cardiology fellow at the Peter Bent Brigham Hospital, recalls, “Though Dr. Dexter had done so much original work himself, he never failed to recognize the outstanding work of others. He generously praised the work of his colleagues.”*

For his contributions to academic, clinical, and scientific medicine, Dr. Dexter was recognized on numerous occasions. He was officially awarded the James B. Herrick Award and the Research Achievement Award of the American Heart Association, the Paul Dudley White Award of the Massachusetts Affiliate of the American Heart Association, the College Medal of the American College of Chest Physicians, and an honorary doctor of science degree from the University of Massachusetts. Whenever Dexter received these prestigious awards, he accepted them with humility. During his speech at Dr. Dexter's memorial service, the Rev. Richard T. Loring (Dexter's nephew) mentioned, “When honors came his way, he was humble enough to be surprised, and never assumed that he deserved them.” 7,25

Lewis Dexter Remembered

Dr. Lewis Dexter considered himself a simple man and prided himself on 2 major contributions—his medical and teaching careers—as evidenced by his obituary in the Boston Globe, which he wrote himself. It states: “Dr. Lewis Dexter … Cardiologist, Taught at Harvard.” 24,26

Dr. Dexter was greatly respected by his students, colleagues, and friends. Dr. Alpert recollected,

I think that everybody who knew Lew Dexter came away from that interaction a better person—a more dedicated physician, a better scientist, and even a better human being. Lew Dexter was always outwardly directed. Even late in his life when he was lying in bed after one of his illnesses or surgeries, he would always consider his visitors, asking, “How are you doing, what's going on with the children, and how are things at home? What's going on with your career?” I try to emulate Lew Dexter every day of my professional career.**

Dr. James Dalen, speaking at Dr. Dexter's memorial service, remembered some of the moments he had shared with Dexter:

When you made rounds with Lew, it didn't take long for you to realize that all his patients loved him. They loved him because he respected his patients and he loved them. In fact, this was the essence of Lew Dexter…. He loved everyone and everyone loved him. 26

On behalf of the next generation of medical students, I salute Dr. Dexter for his lasting contributions to academic, clinical, and scientific medicine, and more importantly, for the outstanding example that he set for us to follow (Fig. 4).

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Fig. 4 Dr. Dexter celebrating his 75th birthday, 1980.

(Photo courtesy of Dr. Joseph S. Alpert; Tucson, Arizona)

Acknowledgments

It has been said that history begins where memory leaves off. Although I never met Dr. Dexter, I have learned about his place in the history of cardiology. More importantly, I have had the privilege of listening to his family, students, and fellows recall their cherished moments with him. For this experience, I am tremendously grateful.

I would like to thank the following people for their contributions, support, and advice: Dr. Joseph S. Alpert (University of Arizona, Health Sciences Center; Tucson, Arizona), Mrs. Sandy Dexter Coburn, Dr. James E. Dalen (University of Arizona, Health Sciences Center; Tucson, Arizona), Dr. Hasan Garan (University of Texas Medical School at Houston; Houston, Texas), Dr. William Grossman (University of California; San Francisco, California), Dr. Virendra S. Mathur (Texas Heart Institute and Baylor College of Medicine; Houston, Texas), and Dr. Paul D. Stein (Henry Ford Hospital and Heart and Vascular Institute; Detroit, Michigan).

I would like to especially thank my professor and mentor, Dr. Heinrich Taegtmeyer (University of Texas Medical School at Houston; Houston, Texas), who first inspired me to write about Dr. Dexter.

Footnotes

* Hasan Garan; interviewed by the author, 30 May 2000.

* Cassandra Dexter Coburn; interviewed by the author, 16 July 2000.

* Virendra S. Mathur; interviewed by the author, 26 May 2000.

** Joseph S. Alpert; interviewed by the author, 15 June 2000.

* Paul D. Stein; interviewed by the author, 20 June 2000.

** Virendra S. Mathur; interviewed by the author, 26 May 2000.

*** William Grossman; interviewed by the author, 28 June 2000.

**** Hasan Garan; interviewed by the author, 30 May 2000.

* Heinrich Taegtmeyer; interviewed by the author, 25 August 2000.

** Joseph S. Alpert; interviewed by the author, 15 June 2000.

Ms Mukhopadhyay is now a 3rd-year student at The University of Texas Medical School at Houston. This essay was a runner-up in the 2000 competition for the Texas Heart® Institute Award for Undergraduate Writing in the History of Cardiovascular Medicine and Surgery.

Address for reprints: Madhuri Mukhopadhyay, MPH, 8310 Fawn Terrace Court, Houston, TX 77071

References

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