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PubMed1996

Hemodynamic effects of a single intravenous injection of synthetic human brain natriuretic peptide in patients with heart failure secondary to ischemic or idiopathic dilated cardiomyopathy.

Synthetic human brain natriuretic peptide (sBNP) is a polypeptide with the same amino acid sequence as the naturally occurring hormone. Preclinical studies have demonstrated that BNP has potent hemodynamic, diuretic, and natriuretic effects that might be beneficial in treating patients with heart failure. This study was a randomized, double-blind, placebo-controlled, ascending-dose trial of sBNP administered as a single intravenous bolus in 27 heart failure patients. Six groups of patients received sequentially increasing doses of sBNP (0.3, 1, 3, 10, 15, and 20 micrograms/kg, respectively) as a single intravenous injection, and hemodynamics were assessed by pulmonary artery monitoring catheter. The 10 and 15 micrograms/kg doses of sBNP resulted in significant reductions in pulmonary capillary wedge pressure (-73%, p < 0.001), mean pulmonary artery pressure (-41%, p < 0.001), mean arterial blood pressure (-28%, p = 0.001), and systemic vascular resistance (-53%, p = 0.004). Significant increases occurred in cardiac index (68%, p < 0.001) and stroke volume index (72%, p < 0.001). The magnitude and duration of hemodynamic changes were dose dependent. There were no adverse effects. sBNP injected as a single intravenous bolus in heart failure patients improves hemodynamics in a dose-related fashion. Further clinical investigations to determine the use of sBNP in decompensated heart failure are clearly warranted.

Cardiomyopathy, Dilated↗
PubMed1997

Usefulness of hemodynamic changes during adenosine infusion in predicting the diagnostic accuracy of adenosine technetium-99m sestamibi single-photon emission computed tomography (SPECT).

Whether adenosine myocardial perfusion single-photon emission computed tomography (SPECT) remains accurate for detecting coronary artery disease (CAD) in the absence of peripheral hemodynamic changes is unknown. To assess the hemodynamic correlates of perfusion defects, we studied 222 consecutive patients (age 71 +/- 11 years) without prior myocardial infarction or revascularization who underwent adenosine technetium (Tc)-99m sestamibi myocardial perfusion SPECT and cardiac catheterization within 6 months of adenosine study. The SPECT protocol used separate acquisition of rest thallium-201 and adenosine Tc-99m sestamibi, which was semiquantitatively analyzed in 20 segments with a visual 5-point scoring system (0 = normal, 4 = absent uptake). The overall sensitivity, specificity, and predictive accuracy of adenosine Tc-99m sestamibi SPECT for detecting significant CAD were 93% (159 of 171), 73% (37 of 51), and 88% (196 of 222), respectively. The study population was grouped into 6 categories as a function of peripheral hemodynamic changes: (1) increase in heart rate by < or = 10 beats/min (n = 135); (2) increase in heart rate by > 10 beats/min (n = 87); (3) decrease in systolic blood pressure by < or = 10 mm Hg (n = 108); (4) decrease in systolic blood pressure by > 10 mm Hg (n = 114); (5) increase in heart rate by < or = 10 beats/min and decrease in systolic blood pressure by < or = 10 mm Hg (n = 72); and (6) increase in heart rate by > 10 beats/min or decrease in systolic blood pressure by > 10 mm Hg (n = 150). The sensitivity, specificity, and predictive accuracy of adenosine sestamibi SPECT were similar in all 6 categories. The prevalence of left main or multivessel CAD and extent of scan abnormality were also similar among all groups. Thus, the diagnostic accuracy of adenosine Tc-99m sestamibi SPECT is high in patients with or without peripheral hemodynamic evidence of adenosine effect.

Adenosine↗
PubMed1998

Hemodynamic profile of submaximal constant workload exercise in patients with heart failure secondary to ischemic or idiopathic dilated cardiomyopathy.

Constant workload exercise on an upright bicycle at submaximal levels of exercise intensity is frequently used in physical training programs. Nevertheless, only a few data are currently available on the hemodynamic changes induced by constant workload exercise in patients with heart failure. The aim of this study was to assess the hemodynamic response during submaximal constant-workload exercise at 2 different work rates in patients with heart failure. The hemodynamic profile was assessed by means of right-sided cardiac catheterization in 21 men with moderate heart failure during submaximal-constant workload exercise performed on an upright bicycle for 15 minutes. The intensity of constant work rate exercise was selected during a previous symptom-limited or maximal test. The first submaximal test was performed at the level of the anaerobic threshold workload, corresponding to 64% of peak work rate, and the other test at 70% of anaerobic threshold workload (42% of peak work rate). During both submaximal tests, a marked increase in right heart pressure was observed as compared with baseline. The increase in systolic pulmonary artery pressure was statistically not different between the 2 tests (from 40 +/- 18 to 66 +/- 20 mm Hg during exercise at the anaerobic threshold workload, and from 39 +/- 16 to 63 +/- 21 mm Hg during exercise under anaerobic threshold). The increase in pulmonary arterial wedge pressure was similar (from 20 +/- 10 to 35 +/- 13 mm Hg during exercise at the anaerobic threshold, and from 19 +/- 9 to 32 +/- 12 mm Hg during the other test). Cardiac output and heart rate were significantly higher during submaximal exercise at a higher workload, paralleling the behavior of oxygen uptake. Finally, the hemodynamic profile during submaximal exercise at the anaerobic threshold workload was quite similar to that observed during symptom-limited exercise. Thus, in patients with heart failure, submaximal exercise performed at a constant workload, even at low exercise intensity, may determine relevant pressure changes in pulmonary circulation.

Aged↗
PubMed1998

Safety and hemodynamic effects of intravenous triiodothyronine in advanced congestive heart failure.

Most patients with advanced congestive heart failure have altered thyroid hormone metabolism. A low triiodothyronine level is associated with impaired hemodynamics and is an independent predictor of poor survival. This study sought to evaluate safety and hemodynamic effects of short-term intravenous administration of triiodothyronine in patients with advanced heart failure. An intravenous bolus dose of triiodothyronine, with or without a 6- to 12-hour infusion (cumulative dose 0. 1 5 to 2.7 microg/kg), was administered to 23 patients with advanced heart failure (mean left ventricular ejection fraction 0.22 +/- 0.01). Cardiac rhythm and hemodynamic status were monitored for 12 hours, and basal metabolic rate by indirect calorimetry, echocardiographic parameters of systolic function and valvular regurgitation, thyroid hormone, and catecholamine levels were measured at baseline and at 4 to 6 hours. Triiodothyronine was well tolerated without episodes of ischemia or clinical arrhythmia. There was no significant change in heart rate or metabolic rate and there was minimal increase in core temperature. Cardiac output increased with a reduction in systemic vascular resistance in patients receiving the largest dose, consistent with a peripheral vasodilatory effect. Acute intravenous administration of triiodothyronine is well tolerated in patients with advanced heart failure, establishing the basis for further investigation into the safety and potential hemodynamic benefits of longer infusions, combined infusion with inotropic agents, oral triiodothyronine replacement therapy, and new triiodothyronine analogs.

Female↗
PubMed1998

Hemodynamics and left ventricular mass regression following implantation of the Toronto SPV stentless porcine valve.

Stentless tissue valves may provide more favorable hemodynamics than conventional stented valves. Hemodynamic findings from a large multicenter trial have not been previously reported. The present report describes the hemodynamic findings from a multinational, multicenter study after implantation of the Toronto SPV valve. A total of 577 patients underwent aortic valve replacement with the Toronto SPV valve at 12 sites in 3 countries. Echocardiograms were recorded in the early postoperative period, 3 to 6 months after surgery, 1 year after surgery, and yearly thereafter, with follow-up to 3 years. Gradients decreased and effective orifice area increased in the months after surgery. One year after surgery, mean gradient for valve sizes 20 to 22, 23, 25, 27, and 29 mm was 7.3 +/- 4.4, 7.4 +/- 4.5, 6.1 +/- 3.3, 4.9 +/- 2.4, and 4.0 +/- 2.1 mm Hg, respectively; effective orifice area was 1.3 +/- 0.7, 1.5 +/- 0.5, 1.7 +/- 0.4, 2.0 +/- 0.4, and 2.4 +/- 0.6 cm2, respectively. There was a very low prevalence of significant aortic regurgitation at all time periods. There was significant left ventricular (LV) mass regression between the early and 3- to 6-month periods and between the 3- to 6-month and 1-year postoperative periods. The Toronto SPV valve has an excellent hemodynamic profile supported by significant regression of LV hypertrophy in the year after implantation. Data through 3 years demonstrates maintenance of low gradients and freedom from significant aortic regurgitation.

Aged↗
PubMed1995

Acute hemodynamic effects of the prostacyclin analog 15AU81 in severe congestive heart failure.

This multicenter, open-label study provides the first assessment of the safety and acute hemodynamic effects of a short-term infusion of 15AU81, a chemically stable analog of prostacyclin, in patients with New York Heart Association class III or IV heart failure. Twelve patients underwent sequential dose escalation by increasing the rate of the infusion at 15-minute intervals until the drug was no longer tolerated. Patients then received a 90-minute infusion at their maximum tolerated dose. The infusion was then discontinued and the subjects were observed during a 90-minute washout segment. Serial hemodynamic measurements were made throughout the dose-ranging, maintenance, and washout segments. A significant decrease in systemic vascular resistance (1,935 +/- 774 vs 1,243 +/- 351 dynes.s.cm-5; p < 0.001) and pulmonary vascular resistance (395 +/- 335 vs 223 +/- 198 dynes.s.cm-5; p = 0.008) occurred from the infusion of vehicle to the maximum tolerated dose. During dose titration, there was a a significant increase in cardiac index (1.9 +/- 0.7 vs 2.6 +/- 0.6 liters/min/m2; p < 0.001) and a tendency for a mild reduction in pulmonary artery wedge pressure (18 +/- 7 vs 17 +/- 6; p = 0.055) for the 8 patients with values on vehicle and maximum tolerated dose. These hemodynamic changes persisted during the maintenance infusion and disappeared rapidly during the washout segment. The most common adverse event to limit dose-ranging was headache, which occurred at a mean maximum tolerated dose of 36 +/- 15 ng/kg/min. Administration of 15AU81 was associated with significant acute hemodynamic improvement in patients with severe heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2000

Latent hemodynamic abnormalities in symptom-free women with a history of preeclampsia.

OBJECTIVE: Most women with a pregnancy complicated by preeclampsia have either hypertension or a disorder with a thrombophilic phenotype or both of these. In this study we evaluated whether hemodynamic variables and volume homeostasis in a subgroup of normotensive women with a history of preeclampsia with normal clotting function (defined as the symptom-free subgroup) were comparable with those in a healthy parous control group. STUDY DESIGN: In a group of 58 subjects with a history of preeclampsia and a group of 11 healthy parous control subjects we measured the following variables > or = 5 months post partum at day 5 +/- 2 of the menstrual cycle: body weight and length, mean arterial pressure, heart rate, cardiac output, plasma volume, glomerular filtration rate, effective renal plasma flow, and plasma concentrations of volume regulatory hormones, clotting factors, antiphospholipid antibodies, and homocysteine before and after a methionine load. From the measured data we calculated body mass index, body surface area, cardiac index, left ventricular work, total peripheral and renal vascular resistances, effective renal blood flow, and renal filtration fraction. RESULTS: Among women with a history of preeclampsia 26 were normotensive with thrombophilia (45%), 14 had hypertension (24%), and 18 were normotensive without thrombophilia (31%). These last symptom-free subjects with a history of preeclampsia were more obese than were control subjects. They also had higher cardiac output and left ventricular work and a lower plasma volume than the healthy parous control subjects. Thus they resemble the second subgroup of subjects (subjects with hypertension and a history of preeclampsia) rather than the control subjects. The hemodynamic and renal functions in the subgroup of subjects with a history of preeclampsia with normotension and thrombophilia were similar to those in healthy parous control subjects. CONCLUSION: On the basis of this study we conclude that hemodynamic parameters and volume homeostasis in the symptom-free subgroup of women with a history of preeclampsia are different from those in healthy parous control subjects. Hemodynamic parameters and volume homeostasis in this subgroup resemble those of women with hypertension and a history of preeclampsia. We therefore propose the classification of these symptom-free subjects with a history of preeclampsia as having "latent" hypertension.

Adult↗
PubMed1999

The effects of retroperitoneal carbon dioxide insufflation on hemodynamics and arterial carbon dioxide.

BACKGROUND: Laparoscopic techniques are being increasingly used for retroperitoneal surgery. However, hemodynamic and ventilatory efforts of retroperitoneal carbon dioxide (CO2) insufflation have not been studied. We hypothesized that differences in absorptive surface, anatomy, and compartment compliance could result in different hemodynamic and ventilatory effects between retroperitoneal and intraperitoneal insufflation. METHODS: Pigs (n = 7) were anesthetized and stabilized. The peritoneal cavity was incrementally insufflated with CO2 to a maximum pressure of 25 cm H2O and the gas released. Hemodynamics and arterial blood gas values were recorded initially, at each level of insufflation, and following the pneumoperitoneum release until baseline values were reached. This insufflation protocol was repeated in the retroperitoneum. RESULTS: Mean arterial pressure (111 mm Hg, 95% confidence interval 99 to 156) and cardiac output (3.7 L/min, 2.8 to 5.2) did not change with increasing insufflation pressure of either intraperitoneum or retroperitoneum. PaCO2 was directly related to insufflation pressure in both spaces, increasing from 41.2 mm Hg (37.3 to 43.4) at baseline to 57.7 mm Hg (47.6 to 82.1) at insufflation pressure of 25 cm H2O. After release of the insufflation gas, time to return to baseline PaCO2 was slightly less from the retroperitoneal space (73 minutes, 45 to 105) than the intraperitoneal (107 minutes, 35 to 175). CONCLUSIONS: The effects of CO2 insufflation on hemodynamics and PaCO2 are the same in the retroperitoneal and intraperitoneal spaces.

Animals↗
PubMed2000

Hemodynamic effects of carbon dioxide insufflation during endoscopic vein harvesting.

BACKGROUND: A prospective study was performed assessing the hemodynamic effects of carbon dioxide (CO2) insufflation during endoscopic vein harvesting (EVH) using the Guidant Vasoview Uniport system. METHODS: Five hemodynamic and respiratory parameters (end-tidal carbon dioxide, arterial partial pressure of carbon dioxide, mean arterial pressure, mean pulmonary arterial pressure, and cardiac output), were measured in 100 consecutive patients undergoing EVH with CO2 insufflation. Data were obtained prior to commencement of EVH, 15 minutes after commencement, and 5 minutes after completion of the vein harvesting. RESULTS: No adverse hemodynamic effects were observed during CO2 insufflation. Specifically, average mean arterial pressure went from 88.77+/-9.64 to 89.13+/-8.60 to 88.24+/-8.71 mm Hg before, during, and after endoscopic vein harvesting (p = 0.291). Likewise, average mean pulmonary artery pressures were 19.76+/-4.75, 20.05+/-4.48, and 20.05+/-4.62 mm Hg (p = 0.547); and average cardiac output was 4.25+/-0.74, 4.22+/-0.73, and 4.23+/-0.69 L/min (p = 0.109) at those three intervals. Additionally, there was no evidence of significant systemic absorption of CO2 as reflected in average arterial PCO2, which remained steady at 37.42+/-5.19, 37.51+/-4.59, and 38.10+/-4.80 mm Hg (p = 0.217); and average end-tidal CO2, which was 32.10+/-3.66, 32.50+/-3.47, and 32.38+/-3.33 mm Hg (p = 0.335). In a subset of 20 patients with elevated pulmonary arterial pressure (more than 32 mm Hg), there was also no significant change in any of the parameters. CONCLUSIONS: Carbon dioxide insufflation during EVH leads to no adverse hemodynamic consequences or systemic CO2 absorption. The technique appears to be safe and well tolerated.

Aged↗
PubMed2001

Hemodynamics and gas exchange during carbon dioxide insufflation for totally endoscopic coronary artery bypass grafting.

BACKGROUND: In addition to single-lung ventilation (SLV), positive-pressure CO2 insufflation is mandatory for totally endoscopic coronary artery bypass grafting. Studies on the effects of unilateral CO2 insufflation on hemodynamics produced controversial results, and bilateral insufflation has not been studied to our knowledge. The present study sought to investigate hemodynamics and gas exchange during unilateral and bilateral CO2 insufflation in patients who underwent totally endoscopic coronary artery bypass grafting. METHODS: Eleven hemodynamic and gas exchange variables were monitored during 22 totally endoscopic coronary artery bypass grafting procedures with unilateral (n = 17) or bilateral (n = 5) CO2 insufflation at a pressure of 10 to 12 mm Hg. Data were obtained at baseline with double-lung ventilation, after institution of SLV, during insufflation, after cardiopulmonary bypass during SLV, and after return to double-lung ventilation. RESULTS: Arterial oxygen tension decreased significantly during SLV, whereas the peak inspiratory pressure increased. In addition, central venous pressure and heart rate increased significantly during insufflation, but mean arterial pressure remained unchanged. Although the end-tidal CO2 pressure did not change, arterial carbon dioxide tension increased progressively to a maximum of 44.6 +/- 5.9 mm Hg during unilateral insufflation, and 55.7 +/- 14.6 mm Hg during bilateral insufflation (p < 0.05 versus baseline and between groups). Mixed venous oxygen saturation declined during SLV regardless of CO2 insufflation and recovered to baseline once double-lung ventilation was restarted. Left and right ventricular ejection fractions remained unaltered. No patient required inotropic or vasopressor support. CONCLUSIONS: Carbon dioxide insufflation for totally endoscopic coronary artery bypass grafting with SLV had no adverse effects on hemodynamics. In contrast to a moderate increase of arterial carbon dioxide tension during unilateral insufflation, markedly elevated arterial carbon dioxide tension levels remain a cause of concern during bilateral insufflation.

Adult↗
PubMed2001

Hemodynamic comparison of second- and third-generation stented bioprostheses in aortic valve replacement.

BACKGROUND: The hemodynamic performance of aortic replacement prostheses is of extreme importance. There is renewed interest in hemodynamics because of the influence of prosthesis-patient mismatch on left ventricular mass regression and the potential influence on survival. METHODS: The hemodynamic performance of the second-generation Carpentier-Edwards supraannular porcine and pericardial (Perimount) bioprostheses and the third-generation Medtronic Mosaic porcine bioprosthesis were compared for mean gradient and effective orifice area index. The effective orifice area index of at least 0.85 cm2/M2 was considered as lack of prosthesis-patient mismatch. The study group included included 53 patients with Carpentier-Edwards supraannular porcine, 48 with pericardial, and 98 with Medtronic Mosaic porcine bioprostheses. RESULTS: The mean gradients were not different between the prostheses by prosthesis size. The Medtronic Mosaic was not provided in size 19. The mean gradients for the prostheses, except in the very large sizes, were all double-digit values. The effective orifice area index was not different between the prostheses but there was a trend toward prosthesis-patient mismatch in smaller size prostheses. CONCLUSIONS: There was no apparent hemodynamic advantage between porcine and pericardial bioprostheses in the aortic position.

Aortic Valve↗
PubMed2001

Pericardial and porcine stentless aortic valves: are they hemodynamically different?

BACKGROUND: We sought to compare the early hemodynamic performance of pericardial stentless aortic valves with that of well-established porcine stentless aortic prostheses. METHODS: A total of 169 patients (97 men and 72 women, aged 73+/-6 years) undergoing aortic valve replacement received either a pericardial (Pericarbon, Sorin Biomedica, Saluggia, Italy; n = 89) or a porcine (Freestyle, Medtronic, n = 80) stentless aortic valve. Aortic valve hemodynamics and root dynamism were assessed by Doppler echocardiography at discharge and 12 months after implantation. RESULTS: Clinical demographic data, valve size (24.0+/-1.9 vs 24.6+/-2.3 mm), and body surface area (1.85+/-0.19 vs 1.80+/-0.19 m2) did not differ between porcine and pericardial valves (both p > 0.05). The 1-year postoperative mean valve pressure gradient (4.2+/-2.6 vs 3.7+/-2.6 mm Hg), effective orifice area (2.2+/-0.8 vs 2.2+/-0.8 cm2), and left ventricular ejection fraction (62+/-13 vs 63+/-13, %) also did not differ (all p > 0.05). However, at discharge, systolic increase in aortic sinus diameter was significantly greater in pericardial valves than in porcine ones (7.7+/-5.7 vs 4.9%+/-4.2%, p < 0.01). Furthermore, pericardial valves had a greater slope of effective orifice area-systolic aortic flow relationship (0.89+/-0.07 vs 0.70+/-0.06, cm2/100 mL/s, p < 0.01). CONCLUSIONS: Nonprosthetic thin-walled pericardial valves appear to offer better aortic root dynamism and more efficient hemodynamics than those of porcine valves immediately after implant. At 1-year follow-up, however, both types of stentless valves provide equally excellent hemodynamics. The clinical choice between the two will depend on their long-term durability.

Aged↗
PubMed2002

Hemodynamic stability during 17 years of the Carpentier-Edwards aortic pericardial bioprosthesis.

BACKGROUND: Long-term stability of the hemodynamic performance of commercially available Carpentier-Edwards stented bovine pericardial aortic bioprostheses (Perimount RSR) is unknown. To anticipate the fate of this bioprosthesis, we examined its hemodynamic performance up to 17 years using echocardiographic studies in a Premarket Approval cohort. METHODS: Of 267 patients at four institutions in the Premarket Approval cohort, 85 had a total of 168 echocardiographic studies during a 17-year period of yearly follow-up examinations. These were reviewed and quantified in a core echocardiographic facility. Longitudinal data analysis was used to account for repeated, censored data. RESULTS: Mean transvalvular gradient was inversely related to prosthesis size (p = 0.01), and possibly (p = 0.06) increased somewhat during the first 10 years of follow-up, then stabilized. Effective orifice area was larger in larger valve sizes (p = 0.01), declined somewhat during the first 10 years, and then began to increase again. Ejection fraction declined minimally (p = 0.2). In contrast to the rather stable hemodynamics, aortic regurgitation steadily increased from none to 1 to 2+ (p = 0.005), but rarely (< 10% at 17 years) progressed to 3+ or 4+. CONCLUSIONS: The Carpentier-Edwards aortic pericardial bioprosthesis can be anticipated to have an acceptable long-term transvalvular gradient and effective orifice size that will change trivially up to 17 years after implantation. Mild aortic regurgitation will develop progressively. This anticipated hemodynamic resilience supports continued clinical use of the Perimount Carpentier-Edwards bovine pericardial stented bioprosthesis.

Adult↗
PubMed2002

Hemodynamic collapse during off-pump coronary artery bypass grafting.

BACKGROUND: The causes of hemodynamic collapse during off-pump coronary artery bypass (OPCAB) remain scarcely defined. We present an analysis of 23 cases of sustained hemodynamic collapse during elective off-pump CABG. METHODS: During a 54-month period, we performed 1420 elective OPCAB procedures through a sternotomy, constituting 71.2% of the total CABG procedures performed. Twenty-three patients (1.6%) experienced hemodynamic collapse intra-operatively requiring immediate cardiopulmonary bypass. Preoperative characteristics, intraoperative data, and postoperative outcome were retrospectively reviewed in each patient. RESULTS: In all cases, improvements in intra-operative technique and/or judgment could be made retrospectively. Twenty (20/23) of these patients had an uneventful postoperative course and three (3/23) patients had an unstable course with two deaths. CONCLUSIONS: The causes of hemodynamic collapse during elective OPCAB were ischemic, mechanical, or a combination of both. A detailed review of our five and a half year experience has revealed a number of suggestions for improving the conduct of the operation.

Aged↗
PubMed2002

Biomechanical modeling of hemodynamic factors determining bulging of ventricular aneurysms.

BACKGROUND: Ventricular aneurysm formation is a frequent complication of transmural myocardial infarction. The hemodynamic determinants of aneurysmal bulging remain unclear. METHODS: A rubber heart placed in a water tank served as an in vitro model. Rhythmic injections of specific volumes into the tank simulated heart beats. The heart rate was adjustable in increments. A section of the heart model's wall was shielded from compression to simulate an aneurysm. To quantitate the relation between hemodynamics and bulging, pressures, echocardiographic measurements of maximal expansion, and mean velocity were recorded. Bulging volume, stroke volume, aneurysmal wall stress, and systemic resistance were calculated. RESULTS: The mean velocity was the echocardiographic factor most closely related to bulging volume (r = 0.92, p < 0.01). When bulging indices were compared with hemodynamics, bulging volume and mean velocity were found to directly depend on heart rate (r = 0.66, p < 0.01; r = 0.70, p < 0.01). Polynomial regression revealed bulging volume to reach minimal values near 80 beats/min. Maximal systolic aneurysmal wall stress was closely related to the peak positive rate of pressure change (r = 0.94, p < 0.01) and moderately to stroke volume (r = 0.75, p < 0.01). Filling pressures were unrelated to bulging. The greatest bulging volume reduction occurred below 790 dynes x s x cm(-5); bulging was practically eliminated at systemic resistance values less than 395 dynes x s x cm(-5). CONCLUSIONS: Aneurysmal bulging and aneurysm formation depend mainly on heart rate, contractility, and afterload. This suggests that hemodynamic management may affect the extent of bulging in a clinical setting.

Biomechanical Phenomena↗
PubMed2003

Clinical and hemodynamic evaluation of small Perimount aortic valves in patients aged 75 years or older.

BACKGROUND: There is the potential for iatrogenic aortic stenosis and poor quality of life when small aortic valve bioprostheses are used in elderly patients. The alternative is enlarging the aortic annulus to accommodate larger size prostheses, increasing operative mortality. It was hoped that bovine pericardial valves would improve hemodynamic performance in the smaller valve sizes. METHODS: To determine long-term results and in vivo hemodynamic performance of small-size aortic Carpentier-Edwards bovine pericardial valves (Perimount) in elderly patients, we analyzed our follow-up and echocardiographic data from patients 75 years of age or older receiving isolated 19-mm and 21-mm Perimount valves. Ninety-four patients with a mean age of 77 +/- 2.2 years were followed for 12 years. Seventeen patients with 19-mm and 25 patients with 21-mm Perimount valves underwent transthoracic echocardiograms. RESULTS: Operative mortality was 6.3% (6 of 94). Twelve-year survival was 82.7%. Freedom from thromboembolism was 86.9% at 12 years. Two patients had anticoagulation-related bleeding. Overall New York Heart Association class decreased from 3 +/- 1 to 1.6 +/- 0.7 at the end of follow-up. Hemodynamic performances were satisfactory in both 19-mm and 21-mm Perimount valves, with low peak and mean transvalvular gradients and good effective orifice areas, orifice area indices, and performance indices. CONCLUSIONS: Perimount aortic valve in the small aortic annulus has yielded excellent long-term results and hemodynamic performances. Perimount is a very satisfactory option in elderly patients. Implantation of a Perimount bioprosthesis avoids enlargement of the small aortic annulus, reducing mortality and morbidity associated with this procedure.

Aged↗
PubMed1998

Fifth-year hemodynamic performance of the prima stentless aortic valve.

BACKGROUND: The medium-term hemodynamic performance of stentless valves has not been widely reported, particularly in comparison with in vitro studies. Therefore, we have assessed prospectively the hemodynamics of the Edwards Prima valve in its fifth year after implantation in the aortic position, and compared the results with those at 1 month after implantation and also with in vitro data. METHODS: Thirty-five patients (age, 77 +/- 6 years; 19 men) were prospectively studied by Doppler echocardiography at 1 month and 52 +/- 8 months after implantation of a Prima stentless valve. Valve hemodynamics were assessed by measuring the mean pressure gradient, mean valve resistance, and effective orifice area. Left ventricular systolic function was quantified by ejection fraction, the degree of hypertrophy by ventricular mass index, and the ratio of ventricular wall thickness to cavity radius as a measure of ventricular geometry. RESULTS: With a mean valve size of 24.6 +/- 2.2 mm in the fifth year after implantation, the mean pressure gradient was 6.2 +/- 3.5 mm Hg, the mean valve resistance, 29 +/- 16 dyne x s(-1) x cm(-5)), and the effective orifice area was 2.05 +/- 0.50 cm2. Compared with 1 month after operation, there was a 47% decrease in mean valve resistance (p = 0.002) and a 39% increase in effective orifice area (p = 0.001). Furthermore, both effective orifice area and mean valve resistance in the fifth year did not differ from their in vitro counterparts, whereas the left ventricular ejection fraction (0.64 +/- 0.14), the left ventricular mass index (119 +/- 49 g/m2), and the ratio of ventricular wall thickness to cavity radius (0.44 +/- 0.13) were within the normal range. CONCLUSIONS: This study suggests that the Prima valve is a reliable stentless aortic bioprosthesis. This is supported by a favorable medium-term clinical outcome, durable hemodynamic performance, and normal mean values of left ventricular ejection fraction and mass index in the fifth year after implantation.

Aged↗
PubMed1999

Myocardial metabolism and hemodynamics during coronary surgery without cardiopulmonary bypass.

BACKGROUND: Although renewed interest has recently been shown in coronary artery bypass grafting without cardiopulmonary bypass, no reports are available on myocardial metabolism and hemodynamics during temporary coronary occlusion and rotation of the contracting heart. METHODS: Changes in myocardial energy metabolism and hemodynamics were monitored in 12 patients undergoing elective coronary artery bypass grafting without cardiopulmonary bypass, and the postoperative efflux of creatine kinase-MB mass and troponin T were also determined. RESULTS: There was a significant increase in myocardial production of ATP degradation products (p = 0.026) and lactate (p = 0.004) during the operation. Myocardial oxygen extraction decreased (p = 0.012) in correlation with use of the short-acting beta-blocker, esmolol (r = -0.71). Apart from a decrease in mean arterial blood pressure (p = 0.002), there were no significant hemodynamic changes during the operation. The overall postoperative troponin T and creatine kinase-MB mass changes remained nonsignificant during the first two postoperative days. One patient had a myocardial infarction, diagnosed by electrocardiography, on the second postoperative day, but otherwise there were no major complications. CONCLUSIONS: Coronary artery bypass grafting without cardiopulmonary bypass seems to be well tolerated as only minor changes in myocardial energy metabolism and hemodynamics are observed during the operation.

Adenosine Triphosphate↗