When Friedrich Mohr Became a “Scientific” Cardiovascular Surgeon

It was early in 1986, when I had started a research fellowship at the Cardiology Department of Cedars Sinai Medical Center in Los Angeles, California. Rumors spread through the department that another fellow from Germany would be joining the Division of Thoracic and Cardiac Surgery at Cedars Sinai for a research fellowship supported by the German Research Foundation (DFG). It was Friedrich Mohr. He had already been trained as a cardiovascular as well as a general surgeon for almost seven years in Bonn, Germany, when he decided to aim at an academic career and to embark on performing translational studies in cardiovascular surgery. He was immediately fully integrated into the experimental research group, not only because of his excellent surgical skills helping us to perform numerous studies in the animal laboratory to assess and quantify myocardial perfusion by various techniques, but also because of his open–minded attitude and unrestricted willingness to help with any experimental procedure.

Friedrich Mohr's research project at Cedars Sinai consisted of developing and validating thermal coronary angiography for the noninvasive assessment of coronary artery bypass graft patency and coronary anatomy in coronary bypass surgery. He realized that recent technical advances in thermographic imaging using new camera systems with higher spatial resolution as well as the possibility for online digital image processing could significantly contribute to increasing the precision of infrared imaging used for thermography. He envisioned that this technique might importantly improve the entirely noninvasive assessment of intraoperative graft patency during coronary bypass graft surgery without using invasive coronary flow probes or electromagnetic flow measurements. In a serious of experimental models, he established the technical requirements for obtaining adequate imaging of bypass graft flow and myocardial perfusion. In collaboration with Jack Matloff, the head of the Division of Thoracic and Cardiac Surgery at Cedars Sinai Medical Center, he translated his experimental findings into clinical application by studying a large series of patients undergoing saphenous vein and internal mammary artery bypass graft surgery. Results of Friedrich Mohr's studies revealed that digital thermal coronary angiography was feasible in patients, allowed for the detection of unsuspected stenosis at the site of distal anastomosis, and likewise delineated the myocardial perfusion area of the applied bypass grafts. His report[1] published on the results of digital thermal coronary angiography in 50 consecutive patients received significant attention in the field of cardiovascular surgery. Later on, Friedrich Mohr extended this technique to assess the patency of internal thoracic artery grafts during minimally invasive direct coronary artery bypass graft (MIDCAB) operations using an endoscopic thermal scanner.[2] His clinical research project at that time comprehensively reflected his passion as a scientifically oriented cardiovascular surgeon, as documented and evidenced throughout his complete ensuing clinical career later on. Friedrich Mohr had extreme enthusiasm for novel technologies and especially digital gadgets. He realized already in his early years of translational cardiovascular research that technological advances not only would enable a considerable extension of cardiovascular surgical procedures, but also improve quality control and thus, in the end, patient safety. However, at the same time he was not afraid to pinpoint some disadvantages of using advanced technologies with respect to thermal coronary angiography. He already reported in his first publication that anatomical restrictions limit the use of this technique to the most proximal parts of the left coronary system, the necessity to extensively tilt the heart to use the camera for assessing the posterolateral left ventricular wall, as well as the limitations imposed by extensive epicardial fat or muscle bridges covering the coronary arteries. Thus, despite his optimistic and forward looking mindset to novel technologies, he was continuously scrutinizing the pros and cons of applying this technique in patients. This critical evaluation of novel techniques is later reflected by his well- balanced view of using robotic surgery for cardiac operations, which he pioneered, at the same time realizing its limitations compared with conventional cardiac surgical procedures.

The second research project Friedrich Mohr was involved in at Cedars Sinai was related to the use of excimer–laser techniques for the treatment of vascular diseases. At that time, the Cardiovascular Division of Cedars Sinai Medical Center was intimately involved in developing this technique for clinical application under the guidance of Frank Litvack and Warren Grundfest. Friedrich Mohr was rather critical with respect to its clinical usefulness for the heart, mainly because he had extensive hands-on experience with coronary atherosclerotic lesions during his surgical procedures and was rather questioning a potential effectiveness of excimer–laser angioplasty. In retrospect, Fred Mohr had more or less already anticipated the failure of laser ablation devices to become a major treatment modality for coronary vascular disease. However, he always admired the spirit of entrepreneurship with which the Cardiovascular Division of Cedars Sinai Medical Center was infected already at that time, realizing that novel treatment modalities would only make it into the clinic if they were growing out of academic research into commercial translation.

Despite his extensive involvement in experimental and clinical research projects at Cedars Sinai Medical Center, Friedrich Mohr also knew at that time that life has additional facets. We both grew up in rural areas in Germany and were working in rather small cities (Bonn and Freiburg, respectively) before coming to Los Angeles. Thus, Los Angeles was the perfect place and a unique opportunity to widen our horizon of life in many aspects. Most memorable, at least two times a week Fred and myself were playing tennis on a floodlit court in the middle of the city from 09:00 to 11:00 pm . On the court, he did overcome minor shortcomings in technical skills with extreme power and seemingly never ending energy, in short, he was a ‘fighter’. After our matches, we always had one or two beers sitting in front of the kiosk of the tennis court. The court keeper left the area at 10:00 pm, but never forgot to put two bottles of Corona outside his kiosk for us. This was the time when we were contemplating on our future career. Very frequently, we were dreaming about directing and leading a heart center together, Fred as the cardiovascular surgeon, myself as the cardiologist, when we would be back in Germany. Essentially, we had the chance to do so two times. We both were almost simultaneously elected as chairs of the respective Departments in Leipzig as well as at the Goethe University in Frankfurt. Friedrich Mohr chose to go to Leipzig, I chose to go to Frankfurt. Despite these decisions, which in retrospect were probably perfect for both us, we remained very close friends over the past 30 years and witnessed the development of therapeutic approaches to cardiovascular diseases in its exceptional pace, in which Fred was a major driver.

I do believe that the way I did get to know Friedrich Mohr during our common time at Cedars Sinai Medical Center anticipated the amazing career he made in the following 30 years with respect to his unique personality: an aficionado of novel technologies with seemingly unrestricted energy and enthusiasm, but at the same time a very warm-hearted and thoughtful advocate for his patients with unsurpassed personal integrity and zest for life.

• References

• 1 Mohr FW, Matloff J, Grundfest W , et al. Thermal coronary angiography: a method for assessing graft patency and coronary anatomy in coronary bypass surgery. Ann Thorac Surg 1989; 47 (3) 441-449
• 2 Mohr FW, Falk V, Philippi A , et al. Intraoperative assessment of internal mammary artery bypass graft patency by thermal coronary angiography. Cardiovasc Surg 1994; 2 (6) 703-710