Marian Ionescu
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Marian Ion Ionescu (21 August 1929 – 12 October 2023) was a Romanian-born British cardiac surgeon. His interest in heart surgery covered several aspects of this specialty. He was an inventor of surgical devices, mostly artificial heart valves, a scientist in the broad term and a medical educator. Ionescu died on 12 October 2023, at the age of 94.


Medicine

Marian Ionescu's entire medical career was dominated by scientific curiosity and a persistent desire and ability to make progress by creating change, by discovering the unknown, by improving the known and by inventing what he thought would be useful. In 1959 in Cleveland, at Dr Kolff's impulse, he created the first 'single leaflet
aortic The aorta ( ; : aortas or aortae) is the main and largest artery in the human body, originating from the left ventricle of the heart, branching upwards immediately after, and extending down to the abdomen, where it splits at the aortic bifurc ...
valve' out of
polyurethane Polyurethane (; often abbreviated PUR and PU) is a class of polymers composed of organic chemistry, organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethane term ...
. This device never went beyond the experimental stage due to
clot A thrombus ( thrombi) is a solid or semisolid aggregate from constituents of the blood (platelets, fibrin, red blood cells, white blood cells) within the circulatory system during life. A blood clot is the final product of the blood coagulatio ...
formation. During 1961 and 1962 in Romania, he conducted, with his team, extensive experimental and clinical work on the
physiology Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ syst ...
of organisms under deep
hypothermia Hypothermia is defined as a body core temperature below in humans. Symptoms depend on the temperature. In mild hypothermia, there is shivering and mental confusion. In moderate hypothermia, shivering stops and confusion increases. In severe ...
, with the aid of extracorporeal circulation, in animals and in man. The body temperature was lowered to between 6 and 15 °C and complete circulatory arrest of up to 56 minutes was maintained without significant negative effects. At Leeds Ionescu designed, created and implanted in the
mitral The mitral valve ( ), also known as the bicuspid valve or left atrioventricular valve, is one of the four heart valves. It has two Cusps of heart valves, cusps or flaps and lies between the atrium (heart), left atrium and the ventricle (heart), ...
position in humans, for the first time ever,
porcine The pig (''Sus domesticus''), also called swine (: swine) or hog, is an omnivorous, domesticated, even-toed, hoofed mammal. It is named the domestic pig when distinguishing it from other members of the genus '' Sus''. Some authorities consid ...
aortic valves attached to a
Teflon Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene, and has numerous applications because it is chemically inert. The commonly known brand name of PTFE-based composition is Teflon by Chemours, a spin-off from ...
cloth collar, starting in February 1967. This was followed by the creation of the
Dacron Polyethylene terephthalate (or poly(ethylene terephthalate), PET, PETE, or the obsolete PETP or PET-P), is the most common thermoplastic polymer resin of the polyester family and is used in fibres for clothing, containers for liquids and foods ...
covered
titanium Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
frame for mounting the porcine aortic valves to be able to implant them in all three cardiac locations (mitral, aortic,
tricuspid The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian heart, at the superior portion of the right ventricle. The function of the valve is to allow blood to flow from the right atrium to the right vent ...
). With various modifications and improvements, these stent mounted valves had been implanted in 87 patients between February 1967 and March 1969. All these valves were treated with
formaldehyde Formaldehyde ( , ) (systematic name methanal) is an organic compound with the chemical formula and structure , more precisely . The compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde. It is stored as ...
and this was the main reason for their limited durability. In a continuous search to create a tissue heart valve which could be used without
anticoagulant An anticoagulant, commonly known as a blood thinner, is a chemical substance that prevents or reduces the coagulation of blood, prolonging the clotting time. Some occur naturally in blood-eating animals, such as leeches and mosquitoes, which ...
treatment, Ionescu created a novel artificial valve. Using
autologous Autotransplantation is the transplantation of organs, tissues, or even particular proteins from one part of the body to another in the same person ('' auto-'' meaning "self" in Greek). The autologous tissue (also called autogenous, autogenei ...
fascia lata The fascia lata is the deep fascia of the thigh. It encloses the thigh muscles and forms the outer limit of the fascial compartments of thigh, which are internally separated by the medial intermuscular septum and the lateral intermuscular sept ...
tissue (the fibrous membrane which covers the outside aspect of the thigh muscles) taken from the patient and used to construct the valve during the operation by mounting the living fascia on a Dacron-covered titanium frame in the shape of a three cusp valve. He began the clinical implantation of these valves in April 1969. This procedure of valve construction and implantation had been used in many centres in the world for about three years until it was realised that fascia lata did not perform well over longer periods of time in the high pressure environment of the left heart. These valves became incompetent after various durations after implantation – from 3 to 12 years. However, two important facts were established by the use of such valves. The
haemodynamic Hemodynamics American and British English spelling differences#ae and oe, or haemodynamics are the Fluid dynamics, dynamics of blood flow. The circulatory system is controlled by homeostasis, homeostatic mechanisms of autoregulation, just as hydrau ...
performance in both mitral and aortic positions was superior to all known artificial heart valves and that the risk of
thrombosis Thrombosis () is the formation of a Thrombus, blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (thrombocytes) and fib ...
and
embolisation Embolization refers to the passage and lodging of an embolus within the bloodstream. It may be of natural origin ( pathological), in which sense it is also called embolism, for example a pulmonary embolism; or it may be artificially induced ...
was minimal when compared with mechanical valves. Freehand insertion of stentless fascia lata aortic valves was also used in a small number of cases with similar results. In his continuous search for the 'Holy Grail', Ionescu experimented with valves made from bovine pericardium (the membrane which surrounds the heart) treated with
glutaraldehyde Glutaraldehyde is an organic compound with the formula . The molecule consists of a five carbon chain doubly terminated with formyl (CHO) groups. It is usually used as a solution in water, and such solutions exists as a collection of hydrates, ...
and mounted on a Dacron covered titanium frame. This original valve, designed and created by Ionescu, demonstrated excellent
hydrodynamic In physics, physical chemistry and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids – liquids and gases. It has several subdisciplines, including (the study of air and other gases in moti ...
performance with good durability during
in-vitro ''In vitro'' (meaning ''in glass'', or ''in the glass'') studies are performed with cells or biological molecules outside their normal biological context. Colloquially called " test-tube experiments", these studies in biology and its subdis ...
fatigue testing. In March 1971 Ionescu began the clinical implantation, for the first time, of this original device. The results were very encouraging. In 1976 Shiley Laboratory in California began to manufacture and to distribute worldwide this valve under the name of 'Ionescu–Shiley Pericardial Xenograft'. Its use by Ionescu and many other surgeons demonstrated very good performance in all aspects until 6 to 10 years post-operatively when signs of malfunction appeared progressively in younger patients and some of the valves had to be removed and replaced. Although a small percentage of the pericardial valves continued to function normally for up to 26 years post-implantation, the majority of them had to be replaced between 6 and 14 years, and a few some time later. In the mid-eighties Shiley Company was acquired by the drug laboratory
Pfizer Pfizer Inc. ( ) is an American Multinational corporation, multinational Pharmaceutical industry, pharmaceutical and biotechnology corporation headquartered at The Spiral (New York City), The Spiral in Manhattan, New York City. Founded in 184 ...
. At around that time a series of severe problems were encountered with the mechanical Bjork–Shiley valve. Some 10 years after the creation of the pericardial valve by Ionescu, and its use by numerous surgeons and after having demonstrated its excellent haemodynamic performance and the reduced propensity for thrombo-embolism, other companies began manufacturing and distributing a plethora of rather similar pericardial valves. None of these showed a better performance than the original Ionescu valve with the exception of a pericardial valve modified and built by Edwards Laboratories and commercialised under the name of 'Carpentier-Edwards Pericardial Bioprosthesis.' This valve is reported to perform better than its predecessor, the original Ionescu–Shiley valve. However, a correct comparison between these two valves cannot be made because the Ionescu valve had been used by most surgeons in patients of all age groups and mostly younger than 65 years, as was the custom in the Seventies and Eighties. The Edwards valve, on the other hand, is being used since the mid-eighties almost exclusively in patients above the age of 65–70 years in whom the risk of primary valve failure is now known to be significantly lower. Ionescu also created the concept of performing multiple sequential haemodynamic investigations of patients following heart valve surgery, to evaluate, in time, the patient's condition. In the field of
congenital heart disease A congenital heart defect (CHD), also known as a congenital heart anomaly, congenital cardiovascular malformation, and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital he ...
, Ionescu was the first surgeon to successfully reconstruct a heart with a single ventricle and continued to use various techniques for the repair of such a complex abnormality. For the repair of congenital
cyanotic Cyanosis is the change of tissue color to a bluish-purple hue, as a result of decrease in the amount of oxygen bound to the hemoglobin in the red blood cells of the capillary bed. Cyanosis is apparent usually in the body tissues covered with ...
cardiac diseases he created and built, initially in his hospital laboratory, two original devices: the 'mono-cusp patch' for the correct enlargement of the narrowed pulmonary artery and annulus and a valved conduit (a tube containing a three-cusped valve) for cases with discontinuity between the
right ventricle A ventricle is one of two large chambers located toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium (heart), atrium, an adjace ...
and the
pulmonary artery A pulmonary artery is an artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs. The largest pulmonary artery is the ''main pulmonary artery'' or ''pulmonary trunk'' from the heart, and ...
. These devices were made of fascia lata and later, using glutaraldehyde treated bovine pericardium. In 1987, Ionescu retired from active surgical work.Gonzalez-Lavin L. (1988) "Letter to the editor, on the retirement of Marian I. Ionescu from clinical practice." ''Journal of Cardiac Surgery,''3,1,85–86 , Ionescu practised high altitude climbing in the Northern Alps and the Himalayas where, during three expeditions, he stood on the top of five peaks around 7000 meters high.


Quotes

"Progress is a continually ascending spiral, a stepwise extension of the horizon and of the quality of knowledge." "The creation of the stented pericardial valve opened a door towards further potential improvements, as this valve, being entirely man-made, lends itself to a multitude of permutations of shape in order to further improve its long term performance."Ionescu M I, Tandon A P, Silverton N P, et al,"Long Term Durability of the Pericardial Valve", ''Proceedings of the Cardiac Prosthesis Symposium III, Montreux, Switzerland, 1985,'' Shiley Incorporated, (1987), Irvine, California


Publications

*242 Original scientific articles on various aspects of cardiovascular and thoracic surgery have been published in several medical journals. *37 Chapters were published in books and treatises *10 Books written/edited as follows: Collective Work (1962) ''Circulatia Extracorporeala si Hipotermia Profunda.'' Ed Academia R.P.R, Bucharest, Romania. Marinescu V., Pausescu E., Ionescu M.I. ''Catecolaminele, Biologie si Patologue.'' Ed Academia R.P.R, (1965) Bucharest, Romania. Ionescu M.I., Ross D.N., Wooler G.H. ''Biological Tissue in Heart Valve Replacement.'' Butterworths, (1972) London. Ionescu M.I., Ross D.N., Wooler G.H. ''I Trapianti Valvorali Cardiaci con Tessuti Biologici.''. Edizioni E.M.S.A., (1972), Napoli. Ionescu M.I., Wooler G.H. ''Current Techniques in Extracorporeal Circulation.'' Butterworths, (!976), London. Ionescu M.I. ''Tissue Heart Valves.'' Butterworths,(1979), London. Ionescu M.I. ''Techniques in Extracorporeal Circulation.'' Butterworths,(1981), London. Ionescu M.I., Cohn L.H. ''Mitral Valve Disease, Diagnosis and Treatment.'' Butterworths, (1985), London. ''The Pericardial Heart Valve - The Odyssey of a Continuously Evolving Concept'' SCTS, (2015) London ''Perspectives in Cardiothoracic Surgery - The SCTS Ionescu University, Volume I'' SCTS, (2016), London


Oral presentations

* 186 Papers presented at different scientific meetings * 122 Lectures given by invitation at various universities and medical centres * 22 Visits for 'round table' or surgical operative demonstrations


Awards

* Member of 23 Scientific Societies * Holder of 6 Fellowships * Obtained 12 Awards and Honorary titles, the latest being the Society of Cardiothoracic Surgery in Great Britain and Ireland Lifetime Achievement Award for Cardiac Surgery (March 2015)


References

{{DEFAULTSORT:Ionescu, Marian Ion 1929 births 2023 deaths Romanian surgeons British cardiac surgeons British inventors British people of Romanian descent People from Târgoviște