Subvalvular gradients in patients with valvular aortic stenosis: prevalence, magnitude, and physiological importance.

BACKGROUND: Although subvalvular gradients in patients with aortic stenosis have been described, their behavior and response to exercise have not been well characterized. METHODS AND RESULTS: Left ventricular and aortic pressures and linear flow velocity were measured with a catheter-tip manometer at rest and during supine exercise in 27 patients with valvular aortic stenosis. A subvalvular gradient was measured in each patient that represented, on average, 48% of the total resting transvalvular gradient. With exercise, both total (rest: 80+/-26 mm Hg; exercise: 90+/-25 mm Hg) and subvalvular gradients (rest: 37+/-13 mm Hg; exercise: 60+/-22 mm Hg) increased significantly. There was a significant inverse relationship between change in exercise cardiac output and total and subvalvular gradients. However, only the exercise subvalvular gradient predicted cardiac output response. CONCLUSIONS: Subvalvular pressure gradients are universally present in patients with severe aortic stenosis and comprise approximately half of the total transvalvular gradient. The extent of exercise cardiac output increase is inversely related to the subvalvular gradient magnitude.

Right heart catheterization in the presence of an inferior vena cava filter.

Inferior vena cava filters are being inserted with increasing frequency. When such patients later require right heart catheterization, brachial or jugular vein access is usually attempted. We describe our experience in 10 consecutive patients using the standard femoral approach, first assessing filter patency and then carefully crossing the filter using a straight guidewire. The right heart chambers were successfully accessed in every case. There were no complications, and in no case did the filter migrate or become dislodged. This technique may prove useful when right heart catheterization is indicated in a patient who has a Greenfield inferior vena cava filter.

Cardiac tamponade in the "new device" era: evaluation of 6999 consecutive percutaneous coronary interventions.

BACKGROUND: The incidence of cardiac perforation and pericardial tamponade appears to be increasing in the era of new coronary interventional devices compared with coronary balloon angioplasty. METHODS AND RESULTS: We reviewed 6999 consecutive percutaneous coronary interventions performed during 1994 to 1996 in a single urban university hospital catheterization laboratory. Data had been collected prospectively as part of an ongoing quality assurance program. Fifteen patients had cardiac tamponade within 36 hours of the procedure. Only 6 of these occurred during the interventional procedure; the others occurred 2 to 36 hours later. The median patient age was 72 years. Nine (60%) patients were female. Three patients received abciximab. Five perforations were at the target coronary artery site, 3 were caused by a guide wire tip in the distal part of the target artery, and 7 represented right ventricular perforations caused by a temporary pacemaker wire. Five of the 7 right ventricular perforations occurred during rotational atherectomy procedures. Diagnosis was aided by immediate echocardiography. Treatment was medical, including pericardiocentesis, in 6 cases. The other 9 patients required surgical drainage and repair. All patients survived the index hospitalization. At 18-month follow-up, 1 patient had died, and all others were without apparent sequelae. CONCLUSIONS: Tamponade after percutaneous coronary intervention is not rare in the "new device" era (overall incidence 0.2%); tamponade after percutaneous coronary intervention is often delayed and may occur outside the catheterization suite; patients are more likely to be female and elderly; immediate echocardiography is an essential aid to diagnosis and prompt treatment; and the use of temporary right ventricular pacing catheters must be reexamined.

Pulmonary and cardiac function in advanced fibrodysplasia ossificans progressiva.

Fibrodysplasia ossificans progressiva is a rare genetic disease characterized by heterotopic ossification in soft tissues. Severe disability results from progressive immobilization of the limbs, jaw, and chest wall. To determine whether cardiac function is altered in this disease, 25 patients ranging in age from 5 to 55 years (disease duration 1-51 years) were studied. History, physical examination, pulmonary functions, electrocardiography, and echocardiography were performed on each patient. Physical examination of the lungs and heart was unrevealing; no right sided ventricular gallops were heard, and no patient was found to have neck vein distention or peripheral edema. The patients had extremely limited chest expansion (1.9 +/- 0.8 inches), suggesting dependence on diaphragmatic breathing. Lung volumes were severely reduced (mean forced vital capacity 44% +/- 14% of predicted), but flow rates were relatively normal. All patients had normal capillary oxygen saturation. Echocardiography was technically difficult, but no abnormalities of left or right ventricular function were seen. Ten (40%) patients had electrocardiographic evidence of right ventricular dysfunction. Compared with patients without such evidence, these patients were older, had significantly longer disease duration, higher hemoglobin, and more impaired pulmonary function. The results of this study suggest that the presence of severely restrictive chest wall disease is associated with a high incidence of right ventricular abnormalities on electrocardiogram. Whether cor pulmonale will eventually occur remains to be determined.

Efficacy and safety of a hemostatic puncture closure device with early ambulation after coronary angiography. Angio-Seal Investigators.

A collagen hemostatic puncture closure device has been developed as an alternative to traditional manual pressure techniques for achieving effective femoral arterial hemostasis after coronary angiography. The purpose of the current study was to determine if patients receiving this device can ambulate safely at 1 hour compared with patients receiving traditional manual pressure and bed rest after sheath removal for diagnostic cardiac catheterization. Patients (n = 304) were randomized to either the device group (n = 202) with ambulation at 1 hour after sheath removal or to the manual pressure control group (n = 102) with ambulation at 4 to 6 hours after sheath removal. The device group achieved earlier time to hemostasis (0.9 +/- 3 vs 17.0 +/- 8 minutes, p = 0.0001) and faster time to outpatient discharge (5.0 +/- 4 vs 7.7 +/- 4 hours, p = 0.0001) compared with the control group. There were bleeding or vascular complications in 19 patients (9%) in the device group and in 6 patients (6%) in the manual pressure group (p = 0.397). In patients undergoing diagnostic coronary angiography, this device, compared with traditional techniques for achieving hemostasis after sheath removal, allows for faster time to effective hemostasis with resultant earlier discharge from the hospital.

Complications of cardiac angiography using low- or high-osmolality contrast agents in patients with left main coronary stenosis.

Recently published guidelines suggest that, in view of cost concerns, low-osmolal contrast should be selectively used in patients at increased risk of experiencing a contrast-related complication during cardiac angiography. The suggested criteria include the presence of left main coronary disease. However, the presence of left main disease is not usually known prior to angiography. Contrast-related complications of cardiac angiography were therefore analyzed in a group of 111 clinically stable patients found to have left main coronary stenosis, to determine if use of low-osmolality contrast had any beneficial effect when compared to standard contrast. Data were gathered prospectively as part of a randomized controlled trial, and the subgroup of patients with left main disease was analyzed retrospectively. Complications were divided into minor, intermediate, and major categories. In the 58 patients who received high-osmolar contrast, there were 4 contrast-related minor reactions, 8 intermediate events requiring treatment, and 1 major adverse event. Among the 53 patients who received low-osmolar contrast, there were no minor reactions, 7 intermediate events requiring treatment, and no major adverse events. The only difference of borderline significance was in the incidence of minor reactions requiring no treatment (P = 0.05). Although small and therefore not definitive, this study suggests that 1) universal use of low-osmolar contrast agents would not be expected to eliminate the risk of contrast-related reactions to cardiac angiography; 2) the well-documented clinical differences between high- and low-osmolar contrast primarily involve mild reactions; and 3) standard high-osmolar contrast is reasonably safe in clinically stable patients with left main coronary stenosis. The results therefore are consistent with the notion that selective use of low-osmolar contrast only in unstable patients is safe and appropriate.

Transluminal extraction atherectomy for aortosaphenous vein graft stent restenosis.

The optimal strategy to manage in-stent saphenous vein graft (SVG) restenosis has not been studied. We present two cases in which transluminal extraction atherectomy (TEC) was used successfully for the treatment of SVG stent restenosis. TEC atherectomy may provide an alternative to conventional balloon angioplasty for such patients.

Femoral artery hemostasis using an implantable device (Angio-Seal) after coronary angioplasty.

Coronary catheter interventional procedures are associated with risk of access site complications. We report our experience with Angio-Seal, an implantable hemostasis device, when used in the femoral artery after coronary angioplasty procedures. Sixty-eight patients were studied. Their average age was 63 years; 84% of the patients were male. All had 8 French access sheaths and received bolus heparin (mean dose 12,690 U). The arterial sheaths were removed an average of 455 min after the conclusion of the procedure, when the activated clotting time was 220 +/- 94 sec (range 97-503 sec). The hemostasis device was successfully deployed in 63 patients (93%). The average time to achieve complete arterial hemostasis was 4.4 +/- 8.9 min (range 0-45). Immediate, total hemostasis without requiring any form of external pressure was obtained in 37 of these patients (54%). the incidence of complications was as follows: significant bleeding occurred in 9 patients (13%); there were 2 hematomas (3%); there were no vascular or infectious complications. One device embolization occurred when the connecting suture broke and the intravascular anchor was lost; no clinical sequelae resulted, and manual hemostasis was successful. In four other patients, the device did not deploy and was removed entirely, followed by uneventful manual hemostasis. Follow-up for 2 months revealed no late sequelae in any patient, and complete absorption of the device was documented by ultrasound study in all cases. We conclude that this implantable device can achieve arterial hemostasis quickly and safety when used in anticoagulated patients after coronary interventional procedures.

Left ventricular diastolic response to exercise in valvular aortic stenosis.

Exercise produces profound alterations in symptoms and hemodynamics in patients with valvular aortic stenosis (AS). Prior studies have demonstrated marked increases in late left ventricular (LV) diastolic filling pressure with exercise. Little information is available on the exercise response of indexes of early LV diastolic performance. Catheter-tip manometer recordings in 11 patients with AS and 5 age-matched controls were obtained at rest and with supine bicycle exercise at the time of cardiac catheterization. Pressure-derived indexes of LV diastolic performance, isovolumic relaxation rate, and diastolic interval data were examined. At rest, early (patients 22 +/- 6 mm Hg, controls 12 +/- 3 mm Hg; p < 0.01), minimal (patients 9 +/- 4 mm Hg, controls 4 +/- 1 mm Hg; p < 0.01), and late (patients 28 +/- 10 mm Hg, controls 13 +/- 3 mm Hg; p < 0.002) LV diastolic pressures were elevated in patients with AS. The time to onset of isovolumic relaxation (patients 422 +/- 31 ms, controls 363 +/- 40 ms; p < 0.01) and minimal LV diastolic pressure (patients 608 +/- 57 ms, controls 448 +/- 52 ms; p < 0.002) at rest were prolonged in patients with AS. With exercise, early (patients 45 +/- 14 mm Hg, controls 15 +/- 3 mm Hg; p < 0.002), minimal (patients 15 +/- 6 mm Hg, controls 2 +/- 1 mm Hg; p < 0.01), and late (patients 38 +/- 10 mm Hg, controls 18 +/- 5 mm Hg; p < 0.002) LV diastolic pressures were elevated, and the time to minimal LV diastolic pressure (patients 528 +/- 26 ms; controls 393 +/- 56 ms) and peak first derivative of LV pressure decline (-LV dP/dt) patients 395 +/- 41 ms, controls 326 +/- 59 ms) were prolonged in AS. Furthermore, patients with AS failed to comparably increase the rate of LV pressure decay and isovolumic relaxation with exercise. The LV diastolic response to exercise in patients with AS is distinguished from the control response by suboptimal and prolonged relaxation and a diminished rate of LV pressure decay. These abnormal responses in early diastolic function coupled with the known abnormal chamber distensibility in AS contribute to significant elevations in early, mid-, and late diastolic pressures with exercise.

Valvular and systemic arterial hemodynamics in aortic valve stenosis. A model-based approach.

BACKGROUND: Assessment of the severity of a stenotic aortic valve has been confounded by reports of flow dependence of stenosis severity. We hypothesized that the pressure gradient at the stenotic aortic valve would be dependent on the characteristics of the arterial circulation. Therefore, clinically useful measures of the severity of aortic valve stenosis may have to take this dependence into account. METHODS AND RESULTS: We developed an analog model of the systemic arterial circulation in the presence of a stenotic aortic valve. The model clearly describes the dependence of stenosis severity (described by coefficients A and B) on the resistive and capacitive properties of the arterial system. We used high-fidelity pressure recordings obtained at the time of diagnostic cardiac catheterizations and found that a highly significant relation between the measured mean transvalvular gradient and that predicted by the model was demonstrated both at rest (r2 = .90) and with exercise (r2 = .80). Furthermore, the relative constancy of stenosis coefficients A and B was validated. CONCLUSIONS: Transvalvular hemodynamics in patients with aortic valve stenosis are dependent on the properties of the arterial system. The current model describes such behavior, correctly predicts the transvalvular gradient from model parameters, and may be useful in the assessment of stenosis severity under various clinical and physiological conditions.

Rapid arterial hemostasis and decreased access site complications after cardiac catheterization and angioplasty: results of a randomized trial of a novel hemostatic device.

OBJECTIVES: This study was performed to test the safety and efficacy of a novel bioabsorbable hemostatic puncture closure device deployed through an arterial sheath. BACKGROUND: Cardiac catheterization procedures are associated with a risk of complications at the arterial access site. Increasing numbers of interventional procedures requiring large sheaths or intense anticoagulation underline the need for secure, rapid methods of obtaining hemostasis at the time of sheath removal. METHODS: We conducted a randomized, multicenter trial in 435 patients undergoing cardiac catheterization or angioplasty at eight participating centers. In 218 patients, hemostasis was achieved using the device (group I); 217 patients were assigned to the manual pressure control group (group II). RESULTS: There were no significant differences in baseline characteristics. Time to hemostasis was considerably shorter in group I (2.5 +/- 15.2 vs. 15.3 +/- 11.7 min [mean +/- SD], p < 0.0001). The deployment success rate for the device was 96%, and 76% of group I patients experienced immediate (within 1 min) hemostasis. Complication rates were lower in group I for bleeding, hematoma and occurrence of any complication. There was no difference in the small incidence of pseudoaneurysm formation. There was no change in either group in the ankle/brachial systolic blood pressure index. Ultrasound follow-up studies 60 days after device deployment revealed complete absorption of the device in all cases. Subgroup analysis revealed particular benefit in patients undergoing interventional procedures. The administration of heparin was associated with a significantly higher complication rate in the manual pressure control group, whereas heparin had no effect on hemostasis time or complication rates in the device group. CONCLUSIONS: This sheath-deployed, bioabsorbable device provides a safe and effective means of obtaining rapid arterial hemostasis after cardiac catheterization procedures. It appears to be particularly useful in those patients most at risk for access site complications.

Immediate arterial hemostasis after cardiac catheterization: initial experience with a new puncture closure device.

A novel device for obtaining arterial hemostasis after invasive procedures was tested in 30 patients undergoing diagnostic catheterization (26 patients) or coronary angioplasty (4 patients). The device is deployed through an arterial sheath and forms a positive mechanical seal both inside and outside the defect in the arterial wall. The components are all bioabsorbable. Thirteen patients received a heparin bolus during the catheterization procedure. The activated clotting time recorded in 15 patients just prior to device deployment averaged 264 sec. 29 of 32 attempted device deployments were successful (91%); and the remaining 3 devices pulled completely out as called for by design in the event of incomplete deployment. Twenty-nine patients ultimately achieved successful hemostasis using the device, with the other patient receiving manual hemostasis. Of these 29, hemostasis was immediate and complete in 19 patients. Light digital pressure was required in another 8 patients for less than 5 min. There was minor delayed bleeding requiring supplemental light pressure in several cases. A total of 11 patients required supplemental pressure in addition to the hemostasis device. The use of bolus heparin was significantly (P = 0.05, Fisher's exact test) related to the requirement for supplemental pressure. Three patients developed hematomas, one of which was present prior to device deployment. The other two patients had received bolus heparin. No patient required transfusion or surgical repair. There was no change in the ankle/brachial systolic blood pressure index after device deployment or at late (30-60 day) follow-up. Ultrasound studies revealed no significant pathology relative to the device.(ABSTRACT TRUNCATED AT 250 WORDS)

Pressure recovery in aortic valve stenosis.

BACKGROUND: Pressure recovery is the variable increase in lateral pressure downstream from a stenotic orifice. The magnitude and clinical significance of pressure recovery in aortic valve stenosis are poorly defined. METHODS AND RESULTS: We obtained high-fidelity pressure and velocity recordings in 11 patients with isolated significant aortic valve stenosis at the time of diagnostic cardiac catheterization. Systematic catheter pullback from the left ventricular cavity revealed a consistent although variable subvalvular gradient. Further pullback across and distal to the region of the stenosed aortic valve revealed a consistent and progressive increase in the ascending aortic pressure. This increase in lateral pressure occurred pari passu with a diminution in amplitude of the velocity pulse. The extent of pressure recovery was directly related to systemic blood flow and transvalvular flow but inversely related to the Gorlin-derived aortic valve area. CONCLUSIONS: These findings have potentially important implications for the hemodynamic evaluation of mild to moderately severe aortic valve stenosis. The extent of pressure recovery may be of additional utility in the assessment of aortic valve stenosis under varying physiological states.

A comparison of low- with high-osmolality contrast agents in cardiac angiography. Identification of criteria for selective use.

BACKGROUND: Controversy exists as to whether low-osmolality radiographic contrast agents, which have less detrimental pharmacological effects but are considerably more expensive than high-osmolality agents, should be used universally or only for selected high-risk patients. METHODS AND RESULTS: A randomized, double-blind study was used to compare the frequency and severity of adverse events in 2245 consecutive patients undergoing diagnostic cardiac angiography. Two thousand one hundred sixty-six patients were successfully randomized to either iohexol, a low-osmolality contrast agent, or diatrizoate (as Hypaque 76), a high-osmolality agent. The end point event included clinically important adverse events (which jeopardized the patient or required aggressive treatment), contrast agent-related procedure abbreviations, and conversion to open-label contrast agent. Clinically important end point events were associated with increased age, New York Heart Association functional class, left ventricular end-diastolic pressure, arteriovenous oxygen difference, severity of coronary artery disease, and history of a previous reaction to contrast agent. End point events were less frequent in patients receiving iohexol (2.6% versus 4.6%; adjusted odds ratio, 1.59; 95% confidence interval, 0.97-2.60; P = .07). The difference in event frequency between iohexol and diatrizoate was confined to the highest-risk quartile of the patient population. An algorithm was developed to classify patients as being at high or low risk for an event based on patient age, New York Heart Association class, history of a prior contrast reaction, and left ventricular end-diastolic pressure. Application of this algorithm for selective use of low-osmolality agents only for high-risk patients to a theoretical population of 1000 patients reduced contrast agent costs 66% without increasing the frequency of contrast agent-related adverse events. CONCLUSIONS: The advantages of low-osmolality contrast agents are clinically important in patients with severe heart disease but are not in less ill patients. Universal use of low-osmolality agents for cardiac angiography in an unselected population is not necessary. Appropriately guided selective use of low-osmolality contrast agents is feasible and has the potential to reduce cost substantially without compromising safety or effectiveness.

Right ventricular-vascular interaction in congestive heart failure. Importance of low-frequency impedance.

BACKGROUND: Vasodilator agents are widely used in congestive heart failure. These agents may have important effects on the pulsatile aspects of right ventricular hydraulic load. METHODS AND RESULTS: Fifteen patients with severe congestive heart failure were studied during cardiac catheterization by use of high-fidelity pressure transducers and a catheter-mounted flow velocity probe. Three graded doses of nitroprusside were infused as pulmonary artery (PA) pressure and flow were continuously recorded. From Fourier transforms of signal-averaged waves, PA impedance, hydraulic power, and wave reflection indices were derived. At the highest dose of nitroprusside (66 +/- 41 micrograms/min), cardiac output was significantly improved, whereas PA mean and wedge pressure, resistance, impedance at the first harmonic, characteristic impedance, and wave reflection amplitude were all reduced. At the dose (32 +/- 20 micrograms/min) at which cardiac output first showed improvement, only PA mean pressure and first-harmonic impedance were significantly reduced. Hydraulic power cost per unit of forward flow was also lowered at this dose, despite lack of significant change in pulmonary vascular resistance. At the lowest dose of nitroprusside (11 +/- 4 micrograms/min), six patients experienced a decrease in stroke volume, whereas the other nine were either unchanged (n = 1) or showed an increase (n = 8). Multiple regression revealed that only the change in first-harmonic impedance correlated with this effect, increasing when stroke volume decreased and decreasing when stroke volume increased (P = .02). The change in first-harmonic impedance at this dose appeared to be caused by alterations in the amplitude of PA wave reflections. At higher doses, changes in mean PA pressure (but not in pulmonary vascular resistance) correlated with changes in stroke volume. CONCLUSIONS: Nitroprusside vasodilation at low doses alters PA hemodynamics in congestive heart failure primarily through changes in low-frequency impedance. In some patients, this effect is associated with decreased stroke output. At higher doses, favorable alterations in resistance, low- and high-frequency impedance, and wave reflections all contribute to increased forward flow and decreased power requirement per unit forward flow. These findings show that ventricular-vascular interaction is importantly affected by pulmonary vasodilation and that appreciation of pulsatile properties is required to understand the effects of pulmonary vasodilation on cardiac output.