American Heart Association Cardiogenic Shock Registry: Design and Implementation.

BACKGROUND: Cardiogenic shock is a morbid complication of heart disease that claims the lives of more than 1 in 3 patients presenting with this syndrome. Supporting a unique collaboration across clinical specialties, federal regulators, payors, and industry, the American Heart Association volunteers and staff have launched a quality improvement registry to better understand the clinical manifestations of shock phenotypes, and to benchmark the management patterns, and outcomes of patients presenting with cardiogenic shock to hospitals across the United States. METHODS: Participating hospitals will enroll consecutive hospitalized patients with cardiogenic shock, regardless of etiology or severity. Data are collected through individual reviews of medical records of sequential adult patients with cardiogenic shock. The electronic case record form was collaboratively designed with a core minimum data structure and aligned with Shock Academic Research Consortium definitions. This registry will allow participating health systems to evaluate patient-level data including diagnostic approaches, therapeutics, use of advanced monitoring and circulatory support, processes of care, complications, and in-hospital survival. Participating sites can leverage these data for onsite monitoring of outcomes and benchmarking versus other institutions. The registry was concomitantly designed to provide a high-quality longitudinal research infrastructure for pragmatic randomized trials as well as translational, clinical, and implementation research. An aggregate deidentified data set will be made available to the research community on the American Heart Association's Precision Medicine Platform. On March 31, 2022, the American Heart Association Cardiogenic Shock Registry received its first clinical records. At the time of this submission, 100 centers are participating. CONCLUSIONS: The American Heart Association Cardiogenic Shock Registry will serve as a resource using consistent data structure and definitions for the medical and research community to accelerate scientific advancement through shared learning and research resulting in improved quality of care and outcomes of shock patients.

Novel epicardial off-pump device for mitral regurgitation: acute evaluation.

OBJECTIVE: This study evaluates the ability of a novel epicardial annuloplasty device Mitral Touch (MAQUET Cardiovascular LLC, San Jose, CA, USA) to reduce functional mitral regurgitation (MR) in a rapid ventricular pacing-induced dilated cardiomyopathy model in dogs. METHODS: A median sternotomy was performed in 13 dogs after MR induction by rapid ventricular pacing (230 beats/min for an average of 35.6 + or - 12.8 days). Two-dimensional epicardial echocardiographic and haemodynamic measurements were performed to evaluate the baseline MR grade, the septal-lateral (S-L) dimension of the mitral annulus, mitral valve (MV) geometry and left ventricular function. The Mitral Touch was implanted by sliding the anterior arm onto the floor of the transverse sinus and positioning the posterior arm just apical to the atrioventricular groove on the left ventricular posterolateral wall. The 24-mm-long device was implanted in eight dogs, the 27-mm-long device in four and the 30-mm standard length device in one. MR grade, S-L dimension and haemodynamics data acquisition were immediately rechecked after device implantation. RESULTS: All implantations, which took only approximately 30s to deploy, were performed on beating hearts without cardiopulmonary bypass. In one early case, after extended manipulation with undersized devices, an atrial laceration was created and bleeding occurred. Design changes were made to eliminate this complication. The MR grade was significantly (p=0.003) reduced from 3.1 + or - 1.1 at baseline to 1.4 + or - 0.8 after device implantation. The S-L dimension at end of systole was also significantly (p=0.001) reduced from 2.7 + or - 0.4 cm at baseline to 2.3 + or - 0.3 cm after device implantation (% reduction: 15.1 + or - 10.6%). The mitral valve coaptation length was significantly (p=0.0001) increased from 0.36 + or - 0.11 cm to 0.50 + or - 0.08 cm, and the mitral valve tethering area was significantly (p=0.0003) decreased from 1.36 + or - 0.38 cm(2) to 0.81 + or - 0.29 cm(2) after Mitral Touch implantation. CONCLUSIONS: This new epicardial device was effective in significantly reducing MR and S-L dimensions acutely on the beating heart without requiring the use of cardiopulmonary bypass. Further studies are necessary to confirm the long-term maintenance of MR and S-L reductions.

Acute feasibility study of a novel device for the treatment of mitral regurgitation in a normal canine model.

OBJECTIVE: : The purpose of this study was to evaluate the implantability of a novel epicardial mitral annuloplasty device and its ability to reduce the septal-lateral (S-L) dimension of the mitral annulus. METHODS: : The devices were implanted on the beating heart in 2 healthy dogs (the 24-mm long device in dog A and the 27-mm and 24-mm standard devices in dog B) by sliding the anterior arm onto the floor of the transverse sinus and positioning the posterior arm just apical to the atrioventricular groove on the left ventricular posterolateral wall. The devices were secured with titanium helical tacks driven through the device into the ventricular wall. Two-dimensional epicardial echocardiograms were performed before and after device implantation to evaluate the degree of mitral regurgitation (MR) and the S-L dimension. RESULTS: : Device implantation was uneventful, taking only ∼30 seconds to deploy. MR (1+) in both dogs at baseline was reduced to zero after implant. The reductions in S-L dimension in systole for the 24-mm device were 7.5% in dog A and 30.5% in dog B. For the 27-mm device in dog B, S-L reduction in systole was 29.9%. The leaflet coaptation length was increased in both cases. CONCLUSIONS: : The new device was effective in reducing S-L dimension and 1+ MR without requiring the use of cardiopulmonary bypass. We are currently evaluating this device for the treatment of MR in a rapid-pacing canine heart failure model.

Effects of single-ventricle physiology with aortopulmonary shunt on regional myocardial blood flow in a piglet model.

OBJECTIVES: In single-ventricle physiology with aortopulmonary connection, diastolic hypotension could alter regional myocardial blood flow. Also, afterload increases could impair myocardial blood flow by increased wall tension and relative subendocardial malperfusion. This study explores the effects of acute single-ventricle physiology on regional myocardial blood flow distribution and investigates the consequences of moderate afterload augmentation on myocardial blood flow. METHODS: Single-ventricle physiology was created in 8 piglets without using bypass, and 8 animals served as a sham control group. Aortopulmonary shunt, echo-guided atrial septostomy, tricuspid valve avulsion, and pulmonary artery occlusion allowed the left ventricle to support systemic and pulmonary circulations. Afterload augmentation was produced by aortic balloon inflation. Physiologic recordings and stable-isotope microsphere determination of myocardial blood flow to the subepicardium and subendocardium were obtained at baseline and during single-ventricle physiology (at 30 minutes, 120 minutes, and afterload increase). RESULTS: Arterial oxygen content, diastolic pressure, and coronary perfusion pressure declined after creation of single-ventricle physiology (P < .05). Acute single-ventricle physiology resulted in higher myocardial blood flow (P < .05), unchanged subendocardial/subepicardial flow ratio and oxygen delivery, and lower coronary resistance (P < .01) as compared with biventricular physiology. Afterload augmentation increased coronary perfusion pressure, causing a trend for higher myocardial blood flow and oxygen delivery (P = NS), without affecting subendocardial/subepicardial flow distribution. Myocardial oxygen supply/demand balance fell in single-ventricle physiology, remaining unchanged during afterload augmentation. CONCLUSIONS: Our study demonstrates that, in acute single-ventricle physiology with aortopulmonary shunt, myocardial blood flow is maintained by lower coronary perfusion pressure. Further, single-ventricle physiology results in less favorable myocardial oxygen supply/demand balance, although normal transmural myocardial blood flow distribution is maintained. Avoidance of diastolic runoff (ventricle-pulmonary conduit) could improve coronary reserve. In our study, moderate afterload augmentation did not induce relative subendocardial malperfusion, nor did it worsen oxygen supply/demand balance.

Near-infrared spectroscopy to monitor cerebral oxygen saturation in single-ventricle physiology.

OBJECTIVES: Near-infrared spectroscopy monitors cerebral oxygen saturation. This parameter parallels jugular venous oxygen saturation and reflects the balance between cerebral oxygen supply and demand. Experience with near-infrared spectroscopy in univentricular physiology is limited. This study explores the relationship between cerebral oxygen saturation, jugular venous oxygen saturation, and other variables of cerebral perfusion in a model of univentricular physiology. METHODS: Univentricular physiology was created in newborn piglets by means of an aortopulmonary shunt, echocardiography-guided atrial septostomy, tricuspid valve avulsion, and pulmonary artery occlusion. Intra-aortic balloon inflation was used to increase afterload. Cerebral oxygen saturation monitoring (INVOS 5100; Somanetics Corp, Troy, Mich), physiologic recordings, and stable-isotope microsphere determination of cerebral blood flow were performed at baseline and after conversion to univentricular physiology (30 minutes, 120 minutes, and during afterload augmentation). RESULTS: Univentricular physiology resulted in lower cerebral oxygen saturation, arterial oxygen content, jugular venous oxygen saturation, and cerebral oxygen delivery. Afterload augmentation increased cerebral oxygen saturation, arterial oxygen content, and jugular venous oxygen saturation, whereas cerebral oxygen delivery was unaffected because of lower cerebral blood flow. Cerebral oxygen saturation predicted jugular venous oxygen saturation, arterial oxygen saturation, and arterial oxygen content. No association was found with cerebral oxygen delivery, which decreased in parallel with cerebral oxygen saturation when the single-ventricle physiology model was established but failed to increase during afterload augmentation. CONCLUSIONS: This study shows that in univentricular physiology cerebral oxygen saturation correlates well with jugular venous oxygen saturation, arterial oxygen saturation, and arterial oxygen content. However, our findings suggest that in singe-ventricle physiology changes in cerebral oxygen saturation need to be interpreted in the context of changes in arterial oxygenation.

Concomitant beating-heart mitral valve surgery and coronary artery bypass in patients with compromised ventricular function.

BACKGROUND: : Surgical repair of mitral valve disease and concomitant coronary artery occlusive disease has high operative risk. Myocardial protection for protracted, complicated procedures is seminal to the overall operative outcome; specifically, preservation of left ventricular function. METHODS: The authors conducted a retrospective review of 25 patients undergoing combined mitral valve repair/replacement (MVR) and coronary artery bypass surgery (CABG) using the beating-heart technique at the Miller/University of Miami School of Medicine. The CABG was performed without cardiopulmonary bypass support. During the mitral valve surgery the perfusion pressure was maintained at 80-90 mm Hg and the systemic temperature at 35-36ºC. The aorta was not cross-clamped. RESULTS: : Twenty-five patients underwent MVR/CABG, including 7 patients with acute myocardial infarction. Preoperative echocardiograms revealed a mean ejection fraction (EF) of 41 ± 4.5%. One patient required a preoperative intraarterial balloon pump. An average of 2.12 ± 0.9 grafts and a total of 10 mitral valve repairs were performed. The average length of stay in the intensive care unit was 14 ± 1.8 days, and average hospitalization time was 23 ± 3. The mean postoperative EF was 41 ± 4.5%. The mortality in this patient group was 12 % (3/25) with a morbidity rate of 52% (13/25). CONCLUSIONS: : The data suggest that the technique is safe and reproducible, and that it potentially has a short-term benefit on left ventricular function. Therefore, this particular technique may be efficacious in patients with compromised left ventricular function requiring a combined MVR/CABG.

Off-pump coronary artery grafting in patients with left main coronary artery disease.

BACKGROUND: Left main coronary artery disease (LMCD) is considered a relative contraindication to off-pump coronary artery bypass (OPCAB) grafting. This study evaluates the safety and feasibility of OPCAB in these patients compared to an on-pump group (cardiopulmonary bypass, CPB) with LMCD. METHODS: Between January 2000 and July 2002, 95 patients with left main coronary artery stenosis >50% underwent coronary revascularization. Seventy-three unselected patients underwent OPCAB and 22 underwent revascularization using CPB. The techniques used for OPCAB included the use of deep traction sutures in the posterior pericardium and stabilizers to expose the distal coronary targets. Intraluminal coronary shunts were routinely used during construction of the anastomoses. Variables were analyzed using a Student's paired t-test with statistical significance defined as p < 0.05. RESULTS: The mean age in the OPCAB group was 59.9 years and the CPB group 61.8 years (p = 0.54). There were 56 males (77%) in the OPCAB and 18 (82%) in the CPB groups. Mean preoperative left ventricular ejection fraction (LVEF) was 40.3% in OPCAB and 47.3% in CPB (p = 0.015). Average number of grafts was 3.1 in OPCAB and 4.1 in CPB (p = 0.0038). There were no conversions to CPB in those patients initially chosen to undergo OPCAB. There were no early deaths in OPCAB. There was one death in CPB. Mean hospital length of stay was 6.9 days for OPCAB and 9.1 for CPB (p = 0.0159). CONCLUSIONS: Patients with LMCD can undergo OPCAB grafting safely and effectively despite reduced LVEF. LMCD should no longer be seen as a contraindication to perform OPCAB grafting.

Distribution of cardiac output and oxygen delivery in an acute animal model of single-ventricle physiology.

BACKGROUND: When single-ventricle physiology is established acutely (ie, after a Norwood procedure), the combination of limited cardiac output and hypoxemia could result in limited oxygen transport to systemic organs. This study investigates the regional distribution of cardiac output and oxygen delivery after creation of single-ventricle physiology. METHODS: Single-ventricle physiology was created in 8 piglets, and 8 other piglets served as sham control animals. Aortopulmonary shunt, echocardiography-guided atrial septostomy, tricuspid valve avulsion, and pulmonary artery occlusion allowed the left ventricle to support systemic and pulmonary circulations. Physiologic parameters and regional blood flow were determined at baseline and at 30 and 120 minutes after conversion to single-ventricle physiology. Parameters were compared by means of 1-way and 2-way analysis of variance. RESULTS: Single-ventricle physiology resulted in lower diastolic arterial pressure, oxygen saturation, and arterial oxygen saturation (P < .05), whereas hemoglobin was unchanged. Cerebral blood flow increased markedly in control animals (P = .04). In contrast, in single-ventricle physiology regional blood flow was unchanged in the brain, higher in the myocardium (P = .1), and mildly reduced in low-priority organs (liver, kidneys, and bowel). Cerebral oxygen delivery increased in control animals, whereas in animals with single-ventricle physiology, oxygen delivery decreased in the brain, liver, kidneys, and bowel (P < .05) and was unchanged in the myocardium. Total-body oxygen delivery decreased in animals with single-ventricle physiology (P < .001) but not in control animals. Total-body oxygen consumption was unchanged in both groups. CONCLUSIONS: This study shows that in acute single-ventricle physiology hypoxemia and limited regional blood flow reduce oxygen transport to low-priority organs and partly to the brain. These findings might contribute to the understanding of gastrointestinal and neurologic complications in children with single-ventricle physiology.

Single-ventricle physiology reduces cerebral oxygen delivery in a piglet model.

BACKGROUND: In single-ventricle physiology, cerebral blood flow and oxygen (O2) delivery may be inadequate. This study tests the hypotheses that in acute univentricular physiology (1) cerebral blood flow increases inadequately to maintain O2 delivery, (2) the brain is incapable of increasing O2 extraction due to hypoxemia, and (3) cerebral O2 delivery diminishes selectively in different brain regions. MATERIAL AND METHODS: Univentricular physiology was created in 8 piglets, while 8 animals were sham controls. Aortopulmonary shunt, echocardiography-guided atrial septostomy, tricuspid valve avulsion, and pulmonary artery occlusion were performed to allow the left ventricle to support systemic and pulmonary circulations. Cerebral blood flow (microspheres), cerebral O2 and lactate metabolism, and cerebral O2 saturation were measured at baseline, 30 minutes, and 120 minutes after conversion to univentricular physiology. RESULTS: Cerebral blood flow increased in the cerebrum and subtentorium in controls (p < 0.05), whereas it remained unchanged in univentricular piglets. Cerebral O2 delivery at 30 and 120 minutes was lower in univentricular physiology than in controls (p = 0.05). Fractional oxygen extraction was unchanged in both groups. Cerebral O2 consumption trended lower in univentricular physiology (p = not significant), while it was unchanged in controls. Lactate cerebral metabolic rate (CMRLactate) increased at 30 and 120 minutes in both groups. The decline in O2 delivery was variable, but present in nearly all brain regions. CONCLUSIONS: This study confirms the hypothesis that, in univentricular physiology, hypoxemia and limited cerebral blood flow reduce cerebral O2 availability in nearly all regions. These findings contribute to the understanding of brain abnormalities in infants with univentricular physiology.

Simultaneous antegrade/retrograde normothermic perfusion with blood (beating heart) for aortic root replacement in acute type-a dissection of the aorta.

A new technique of myocardial protection was utilized in performing surgery for acute type-A dissection involving the aortic valve, requiring replacement of the root. Simultaneous antegrade and retrograde perfusion of the heart with normothermic blood at high flows allows for safe and precise surgery, without concerns for the period of aortic clamping, since ischemia is eliminated altogether.

The history and development of direct coronary surgery without cardiopulmonary bypass.

The history of direct myocardial revascularization without cardiopulmonary bypass dates to 1961 in the dawn of coronary artery surgery. With the introduction and development of techniques of extracorporeal circulation around the same time, beating heart surgery was largely abandoned. Over the subsequent decades, cardiopulmonary bypass and electromechanical cardioplegic arrest became popular as means of revascularization in a bloodless and motionless field. While coronary artery surgery on the arrested heart remained undisputed for decades, myocardial revascularization on the beating heart was pursued by a few pioneering surgeons around the world, based on the belief that coronary revascularization could be performed equally well without the detrimental effects of cardiopulmonary bypass and electromechanical arrest. Various concepts and techniques developed during the 1980s by these pioneers enabled minimally invasive coronary surgery to be performed in the early 1990s. This break from the mainstream allowed selective myocardial revascularization using a minimal incision and no cardiopulmonary bypass to develop and constructed a base for future extensive revascularizations off-pump. With the subsequent explosion of new techniques for coronary exposure and myocardial stabilization, complete revascularization without cardiopulmonary bypass became possible with consistent results. Emerging from the preview of only a few surgeons just a decade ago, off-pump surgery is currently one of the accepted modalities for complete myocardial revascularization worldwide. This paradigm shift in the approach to myocardial revascularization has led to exiting new future possibilities, such as beating heart totally endoscopic coronary artery surgery.

Beating-heart valve surgery in patients with renal failure requiring hemodialysis.

BACKGROUND AND AIM OF THE STUDY: The safety and efficacy of beating-heart valve surgery as a myocardial protection strategy was evaluated in patients with renal failure requiring hemodialysis. METHODS: This was a retrospective review of nine patients (four males, five females; mean age 46.7 years; mean duration of hemodialysis 47 +/- 49 months) who underwent beating-heart valve surgery at the present authors' institution between April 2000 and September 2002. RESULTS: The mean cardiopulmonary bypass time was 77.2 +/- 8 min. Perioperatively, two patients died (one from sepsis; one from complication of anticoagulation). There were no deaths in the follow up since discharge, with average follow up 18.3 months (range: 9-27 months). Other complications included reintubation for <24 h (one case), AV graft thrombosis (one patient) and stroke (one patient, as mentioned above). There were no new cardiac (including arrhythmia and low cardiac output syndrome) or metabolic complications (including hyperkalemia and fluid overload). CONCLUSION: This is the first report of beating-heart valve surgery using simultaneous antegrade and retrograde perfusion with normothermic blood. Despite being small in size, the study demonstrated the safety of this approach in a high-risk population with renal failure requiring hemodialysis. The results suggested a low incidence of complications, and short ICU and hospital stays.

Beating heart aortic valve replacement in a pregnant patient.

A 23-year-old woman with a history of previous bileaflet mechanical aortic valve replacement presented in acute heart failure at 27 weeks of gestation. Transthoracic echocardiography (TEE) demonstrated minimal leaflet excursion consistent with valve thrombosis. The patient underwent emergent surgery with normothermic cardiopulmonary bypass (CPB), and beating-heart technique for valve replacement. This novel strategy for aortic valve replacement is being presented as being particularly useful in pregnant patients whose fetuses are at risks of hypothermia, hemodilution, and hyperkalemia during CPB.

Initial experience with sutureless proximal anastomoses performed with a mechanical connector leading to clampless off-pump coronary artery bypass surgery.

BACKGROUND: We report our early experience with the Symmetry Aortic Connector (St. Jude Medical, St. Paul, MN) used for sutureless proximal aortosaphenous vein graft anastomoses without any cross clamp during coronary bypass procedures. METHODS: Between November 2001 and August 2002, 206 saphenous vein to aorta proximal anastomoses were created in 132 patients using the Symmetry device. All procedures were performed as part of off-pump coronary artery bypass surgery without any aortic clamping. Intraoperative variables and postoperative data were collected and analyzed retrospectively. RESULTS: All 206 anastomoses (100%) were successfully completed with the connector. Severe atherosclerotic disease of the aorta was documented in 16 patients (12%). Four anastomoses (2%) required additional suture placement. Predeployment problems occurred with 3 grafts (2.5%) during loading of the connector. Average number of distal bypasses was 3.2 per patient. One patient (0.7%) required reoperation for bleeding from a proximal anastomosis. Six patients (4.5%) had perioperative myocardial infarction documented by electrocardiographic changes. Thirty-day operative mortality was 3% (4 patients). Intraoperative transit time flow measurement was performed in all cases (100%). Postoperative angiography in 43 patients at a median 3 months postoperatively revealed occlusion of 9 of the 81 saphenous vein grafts (11%). CONCLUSIONS: The initial experience with a proximal saphenous vein graft to aorta anastomosis using the Symmetry connector demonstrates safety and ease of use. There is however some concern with early graft closure. A prospective randomized study is needed to clarify these concerns.

Passive constraint and new shape-change devices for heart failure.

Lessons learned from ventricular remodeling procedures have shown that Laplace mechanics, whereby mural tension is related to ventricular diameter, may be beneficially applied to the left ventricle (LV). Recently developed devices, predicated on the Law of Laplace, are directed at interrupting the heart-failure cascade without removing functioning myocardium. The Acorn cardiac support device is a polyester-mesh jacket placed snugly around the heart to provide end-diastolic support and prevent LV dilation. The Myosplint device uses transmural tension members to bisect the dilated LV to create a bilobed LV with decreased mural tension in each cavity. Preclinical and early clinical data with both devices appears promising and may offer a new surgical alternative for patients with worsening heart failure.