Desarrollo histórico de la protección miocárdica: el gran salto adelante de la cirugía cardiovascular / Historical development of myocardial protection: the big jump ahead of cardiovascular surgery

La cirugía a "corazón abierto" con circulación extracorpórea se apronta a cumplir 70 años. Desde un comienzo se hizo necesario buscar la forma de tener un campo operatorio quieto y exangüe, sin riesgo de embolia aérea, lo que llevó al desarrollo de la primera "cardioplegía" por Melrose, a fines de los años 1950's. Sin embargo, esta cayó en descrédito rápidamente y fue abandonada en años 1960's. Se necesitó que transcurrieran casi 15 años para el retorno de la cardioplegía, ahora como forma de proteger al corazón de la isquemia. Durante este periodo se volvió a la fibrilación ventricular a la perfusión coronaria, al paro isquémico y a la hipotermia tópica. Sin embargo, algunos investigadores mantuvieron su interés en la cardioplegía, facilitando el retorno clínico de esta con Hearse en 1976, con la solución cardioplégica cristaloide del Hospital St. Thomas, la que se asentó como el principal método de protección miocárdica, hasta la irrupción de Buckberg con su cardioplegía sanguínea en multidosis, la que se convirtió, a comienzo de los años 1990's, en el procedimiento preferido para proteger al corazón durante el periodo de isquemia requerido para operar en él, infundida ahora no solo por vía anterógrada, sino que también por vía retrógrada. Esto, hasta Pedro Del Nido y su vuelta a la dosis única, solo por vía anterógrada.

Open heart surgery with extracorporeal circulation is approaching its 70th anniversary. From the beginning it was necessary to find a way to have a still and bloodless operative field, without the risk of air embolism, which led to the development of the first "cardioplegía" by Melrose, at the end of the 1950's. However, it quickly fell into disrepute and was abandoned in the 1960's. It took almost 15 years for cardioplegía to return, now as a way of protecting the heart from ischemia. During this period, ventricular fibrillation, coronary perfusion, ischemic arrest and topical hypothermia returned. However, some investigators maintained their interest in cardioplegía, facilitating the clinical return of cardioplegía with Hearse in 1976, with the crystalloid cardioplegic solution of St. Thomas's Hospital. This became the main method of myocardial protection until the irruption of Buckberg with his multidose blood cardioplegía, which became, at the beginning of the 90's, the preferred method to protect the heart during the ischemic period required to operate on it, now infused not only by anterograde route but also by retrograde route. This, until Pedro Del Nido and his return to the single dose, only via the antegrade route.

[Operating upon the Bloodless Heart : A History of Surgical Time between Craft, Machines and Organisms, 1900-1950]. / Operieren am blutleeren Herzen : Eine Geschichte chirurgischer Zeit zwischen Handwerk, Maschinen und Organismen, 1900­1950.

Up until now time has rarely been considered in the historiography of surgery. However, the emergence of modern operating procedures is based significantly on establishing controlled relations of time by adjusting organic, technological and organizational processes. Early cardiac surgery in particular faced a crucial time problem: excluding the heart from the circulatory system long enough to operate inside its bloodless chambers. This problem can be traced back to the early 20th century, when surgeons such as Ludwig Rehn (1849-1930), Friedrich Trendelenburg (1844-1924), and Alexis Carrel (1873-1944) experimented with occlusions of the great vessels. Throughout the first half of the century, various attempts were made to prolong the possible time of circulatory arrest. In this regard, Arthur W. Meyer (1885-1934) in Berlin developed surgical craft procedures, John H. Gibbon Jr. (1903-1973) worked on constructing a heart-lung machine in Boston/Philadelphia, and Wilfred G. Bigelow in Toronto experimented with lowering the temperature of the body. Meticulous scrutiny of these developments illustrates how heterogeneous periods, rhythms, and paces had to be harmonized in order to gain decisive minutes or even seconds. Therefore, major developments on the way to open heart surgery can be described as a history of surgical time.

Cardiac standstill and circulatory flow arrest in surgical treatment of intracranial aneurysms: a historical review.

Since the first surgery for an intracranial aneurysm in 1931, neurological surgeons have long strived to determine the optimal methods of surgical correction. Significant challenges of aneurysm clipping include intraoperative rupture and complex dome morphology. Hypothermia, cardiopulmonary bypass, pharmacologically induced hypotension, and cardiac standstill are a few of the methodologies historically and currently employed in the management of these issues. In the 1980s, significant advances in pharmacology and anesthesiology led to the use of agents such as adenosine for chemically induced hypotension and eventually complete circulatory arrest. Since the institution of the use of these agents, the traditional methods of circulatory arrest under conditions of hypothermia and cardiopulmonary bypass have fallen out of favor. However, there still exists a subset of technically difficult aneurysms for which cardiac standstill, both chemical and hypothermic, remains a viable therapeutic option. In this paper, the authors describe the history of cardiac standstill by both hypothermic and chemically induced means as well as provide examples in which these techniques are still necessary.

Myocardial protection in cardiac surgery: a historical review from the beginning to the current topics.

Myocardial protection has become an essential adjunctive measure in cardiac surgery for a couple of decades, because since the 1950s, the methods of cardioprotection (cardioplegic solutions and related procedures) have been improved by the mechanism of myocardial ischemia/reperfusion-induced damage being unveiled through the untiring efforts of researchers and clinicians. The concept of myocardial protection in cardiac surgery was proposed along with introduction of hypothermic crystalloid potassium cardioplegia in the beginning and has been diversified by pharmacological additives, blood cardioplegia, temperature modulation (warm; tepid), retrograde cardioplegia, controlled reperfusion, integrated cardioplegia, and pre-and postconditioning. This historical review summarized experimental and clinical studies dealing with the methods and results of myocardial protection in cardiac surgery, introducing the newly developed concepts for the last decade and the current topics.

History and use of del Nido cardioplegia solution at Boston Children's Hospital.

Cardioplegia is an integral and essential method of myocardial protection for patients of all ages requiring cardiac surgery in which the heart must be stopped. Numerous cardioplegia solutions and delivery methods have been developed. The del Nido cardioplegia solution has been in use for 18 years at Boston Children's Hospital. This is a unique four parts crystalloid to one part whole blood formulation that is generally used in a single-dose fashion. Although the formulation was originally developed for use in pediatric and infant patients, its use for adult cardiac surgery has been expanding. National and international inquiries to our institution regarding this cardioplegia have been increasing over the last 2 years. We present the developmental history, supporting theory, and current protocol for use of what is now referred to as del Nido cardioplegia.

Warm pediatric cardiac surgery: European experience.

Cold pediatric cardiac surgery has been a dogma for 50 years. However, the beneficial effects of cold perfusion are counterbalanced by the drawbacks of hypothermia. Thus, we propose a major paradigm shift from hypothermic surgery to warm perfusion and intermittent warm blood cardioplegia. This approach gives satisfactory results even with prolonged aortic crossclamp times. The major advantages are reduced time to extubation and shorter intensive care unit stay. Warm pediatric surgery is an anecdotal phenomenon no more; over 10,000 procedures have been carried out in Europe. All types of cardiopathy have been treated, including arterial switch, total pulmonary anomalous venous return, interruption of the aortic arch, and hypoplastic left heart syndrome. Once surgeons decide to shift from hypothermia to normothermia, they never decide to shift back to hypothermia. This fact is evidence of the satisfactory clinical outcome obtained with this technique. The technique and the composition of microplegia is identical in all European centers, the only variable factor being the interval between microplegia injections, which varies from 10 to 25 min. We hope that the increasing interest in pediatric warm surgery will hearten new candidates.

Arch reconstruction without circulatory arrest: historical perspectives and initial clinical results.

For many years, deep hypothermic circulatory arrest had been a necessary and unavoidable adjunct to surgical procedures including aortic arch reconstruction in neonates and infants. Despite meticulous investigation of bypass techniques for deep hypothermic circulatory arrest, unfavorable long-term neurologic deficits have been well documented. Currently, several cerebral perfusion techniques are used in neonatal arch reconstruction to avoid circulatory arrest and prevent brain ischemia. The techniques and their initial clinical results are presented and related problems discussed. Currently available circulatory arrest techniques should be avoided in favor of well-established continuous perfusion techniques, even for arch reconstruction.

Myocardial protection: the rebirth of potassium-based cardioplegia.

The introduction of open-heart surgery more than 4 decades ago signaled a new era in medicine. For the 1st time, previously untreatable cardiac anomalies became amenable to surgical therapy. The use of the heart-lung machine seemed to grant the surgeon unlimited time in which to operate inside the heart. Still frustrated by poor operating conditions and the threat of air embolism, Denis Melrose introduced elective cardiac arrest in 1955. His use of a potassium citrate solution seemed to offer a safe method to effect a quiet, bloodless field. However, a few years after its inception, numerous reports began to question the safety of this approach, and the Melrose technique was abandoned in the early 1960s. Nearly 15 years elapsed before potassium-based cardioplegia regained popularity. During this period, topical hypothermia, coronary perfusion with intermittent aortic occlusion, and normothermic ischemia were evaluated and discarded. A few European investigators like Hoelscher, Bretschneider, and Kirsch had maintained their interest in chemical cardioplegia, and it was through their efforts that future researchers like Hearse and Gay spearheaded the return to potassium-based cardioplegia, which today forms the core of the cardiac surgeon's myocardial protective armamentarium and has contributed towards lowering operative mortality rates.

Milestones in the development of cardioplegia.

Long before there was a possibility for the application of cardioplegia to clinical situations, physiologists and surgeons studied the influence of various cations on function of the myocardial cell. These monumental studies helped set the stage for the eventual practical application of various means of myocardial preservation once open cardiac surgical techniques became available. This presentation attempts to summarize early research effort from the work of Sidney Ringer in 1878 until the present time. The historical progression of myocardial protective strategies is reviewed in a sequential fashion, highlighting major contributions and practices of investigators at the time. It is hoped that such a review of the accomplishments of our colleagues past and present will improve our perspective regarding current applications of such knowledge and that it may stimulate further inquiry toward improving present-day myocardial preservation strategies.

Direct-vision aortic valvotomy: predecessor to modern aortic surgery.

In 1956, Swan and Kortz described a direct-vision aortic valvotomy performed through a transaortic approach during caval occlusion and moderate hypothermia. The rationale for this approach was based on careful thought and review of relevant information that was available at that time. Although cardiopulmonary bypass has since supplanted inflow occlusion to enable exposure of the aortic valve during operation, the principles considered by Swan and Kortz have survived decades of change. Their contribution heralded the beginning of modern aortic surgery while demonstrating the carefulness of thought supported by the audaciousness of conviction that characterizes innovation in surgery.

Perspectives on myocardial protection: warm heart surgery.

Continuous normothermic blood cardioplegia (CNBC), was recently introduced into clinical cardiac surgery and has generated great interest. CNBC represents the evolution of concepts which were initially described in the 1950s but which were forgotten as hypothermia became the main ingredient in all cardioplegic techniques and in heart surgery in general. The historical background to the development of CNBC is presented, as well as a review of the current state of knowledge about normothermic heart surgery. The limitations and pitfalls of the method are highlighted, along with future developments and perspectives.