Blade Balloon Atrial Septostomy in Patients With Severe Primary Pulmonary Hypertension
Background Patients with severe primary pulmonary hypertension have a poor prognosis, but those with a patent foramen ovale may survive longer. A few reports of clinical improvement after blade balloon atrial septostomy in patients with severe pulmonary vascular disease have appeared. The purpose of this study was to systematically evaluate the effects of blade balloon atrial septostomy on clinical signs and symptoms, hemodynamics, and survival in patients with severe primary pulmonary hypertension.
Methods and Results Blade balloon atrial septostomy was performed on 15 children and young adults with severe primary pulmonary hypertension. Despite maximal medical therapy, prior to septostomy all patients had recurrent syncope and 8 had severe right heart failure. Thirteen patients survived the procedure. After blade balloon atrial septostomy, no patient experienced further syncope, and signs and symptoms of right heart failure improved in all New York Heart Association Class IV patients. Within 24 hours after the procedure and at follow-up catheterization 7 to 27 months after septostomy, there was a significant increase in cardiac index, resulting in an increase in systemic oxygen transport. There was improved long-term survival in the 13 patients who survived blade balloon atrial septostomy compared with similar groups of primary pulmonary hypertension patients who received standard therapy (P<.05).
Conclusions Blade balloon atrial septostomy resulted in clinical and hemodynamic improvement and improved survival in selected patients with severe primary pulmonary hypertension.
Primary pulmonary hypertension is characterized by progressive elevation of pulmonary artery pressure, which eventually leads to right ventricular failure and death. Without treatment, the mean survival after diagnosis in children is less than 1 year,1 and in adults it is between 2 and 3 years.2 Patients with severe right heart failure (New York Heart Association [NYHA] Class IV) have the worst prognosis, with a median survival of 6 months.2 Right atrial pressure, pulmonary artery pressure, and cardiac index have been shown to be correlated with mortality.3 Patients with primary pulmonary hypertension and a patent foramen ovale have been reported to live longer than patients without a patent foramen ovale.4
After early animal studies by Austen et al5 showed that an interatrial communication allowed decompression of a hypertensive right ventricle and augmentation of systemic blood flow, particularly during exercise, blade balloon atrial septostomy was first reported as palliative therapy for refractory primary pulmonary hypertension in humans in 1983.6 Between 1981 and 1986, Nihill et al7 successfully performed blade balloon atrial septostomy in 8 patients with advanced pulmonary vascular disease and severe right heart failure. Two of the patients had mild clinical improvement and 4 patients markedly improved.
The purpose of this study was to evaluate the effects of blade balloon atrial septostomy on clinical signs and symptoms, hemodynamics, and survival in patients with severe primary pulmonary hypertension and to determine the role of this approach in the systematic management of patients with this disease.
Between June 1990 and January 1992, we performed blade balloon atrial septostomy in 15 patients with severe primary pulmonary hypertension (Table 1⇓). The patients’ ages ranged from 7 to 39 years (mean, 25 years). Thirteen of the patients were female and 2 were male. Thirteen patients had recurrent syncope and 2 had recurrent near-syncope (dizziness or light-headedness associated with exertion or cough) despite maximal medical therapy (which included digoxin, diuretics, warfarin, and oxygen). Seven patients were in NYHA Class III and 8 had severe right heart failure (NYHA Class IV). Three of the NYHA Class IV patients were in the intensive care unit receiving intravenous inotropic support prior to blade balloon atrial septostomy. Two of these patients had been admitted to the intensive care unit on an emergency basis and started on intravenous inotropic support, and were on maximal cardiorespiratory support at the time of the procedure. One additional patient was electively started on intravenous inotropic support prior to septostomy. In all patients, hemodynamics had been previously defined at cardiac catheterization. Eleven patients had had acute vasodilator drug testing during cardiac catheterization. Six patients were being treated with oral or intravenous vasodilators on the basis of a favorable response (n=4) or lack of an adverse response (n=2) to acute testing, as defined by previously published protocols.8 9 Five patients were not being treated with vasodilators because of an adverse response to acute testing. Two patients (10 and 13) had been empirically started on oral vasodilators before being referred to Columbia Presbyterian Medical Center. Because patient 13 did not improve clinically and did develop rapidly progressive right heart failure shortly after starting nifedipine, the drug was discontinued. Two patients (6 and 14) had not had acute vasodilator drug testing because of the high risk of mortality from cardiac catheterization with such testing predicted on the basis of these patients’ performance on exercise tests.10
Before blade balloon atrial septostomy, all patients underwent an extensive evaluation including a complete history, physical examination, and laboratory evaluation. Noninvasive studies included an ECG, chest radiography, and a two-dimensional echocardiogram with a cavitation study to rule out an anatomic interatrial communication. Multiple gated acquisition studies and exercise testing were also performed. Patients were considered candidates for blade balloon atrial septostomy if they had recurrent syncope or near-syncope despite maximal medical therapy. Systemic arterial saturation had to be greater than 92% at rest so desaturation, a result of right-to-left atrial shunting, would be tolerated after septostomy. Despite right ventricular dysfunction, left ventricular function had to be normal, as defined by a left ventricular ejection fraction greater than 55% on a multiple gated acquisition study, so the additional volume load to the left ventricle would be tolerated. Systemic arterial oxygen desaturation with exercise, in addition to a positive cavitation study demonstrating right-to-left atrial shunting, defined an “adequate” interatrial communication and excluded patients as candidates for blade balloon atrial septostomy. Informed consent was obtained from all patients or their parents.
Before septostomy, all patients were transfused with packed red blood cells to achieve a hematocrit greater than 40% to enable them to maintain adequate systemic oxygen transport after the procedure. To prevent hypovolemia, diuretics were stopped 12 hours before cardiac catheterization. Eight hours before blade balloon atrial septostomy, patients were given nothing by mouth and maintenance intravenous fluids were started. Patients were sedated with meperidine, promethazine, and either chlorpromazine or scopolamine administered by an intramuscular injection. Oxygen was administered through a face mask or nasal cannula after sedation. Three patients were also treated with intravenous dobutamine or amrinone to optimize cardiac function.
After placement of an arterial catheter to monitor systemic arterial pressure, right heart catheterization was performed, and a Swan-Ganz catheter was left in the main pulmonary artery for the remainder of the procedure. Because transseptal catheterization cannot be performed via the superior vena cava and is technically easier by using the right femoral vein, via the right femoral vein left heart catheterization was then performed transseptally, using the Brockenbrough transseptal needle and a 9F or 10F Mullins transseptal dilator and long sheath. After transseptal puncture, the dilator and needle were slowly withdrawn and blood was aspirated from the sheath. The long sheath, now in the left atrium, was on a continuous heparin flush. Blade atrial septostomy was performed using the 13.4-mm Park blade catheter in 2 patients, the 13.4-mm blade followed by the 20.0-mm blade in 1, and the 20.0-mm blade catheter in 11. After the blade catheter was advanced through the sheath into the left atrium, the long sheath was withdrawn to the level of the inferior vena cava. The blade, extended to an angle of approximately 45° and directed inferiorly, was slowly withdrawn across the atrial septum. The blade catheter was slowly withdrawn and, by use of a Lehman catheter through the long sheath, the sheath was repositioned in the left atrium (Ref 11 and M.R. Nihill, MD, C.E. Mullins, MD, personal communication, 1990). At orthogonal angles, three to six blade incisions were then performed in each patient in an attempt to decrease the systemic arterial oxygen saturation by 5% to 10% from baseline. Balloon atrial septostomy was subsequently performed in 11 patients by use of Mansfield valvuloplasty balloon catheters with diameters ranging from 4 to 18 mm. Hemodynamic measurements were repeated at the end of the procedure. All patients were monitored in the intensive care unit for at least 24 hours after the procedure. Nine patients required 1 to 5 units of additional packed red blood cells to maintain a hematocrit greater than 40%. Hemodynamic measurements were repeated 24 hours after blade balloon atrial septostomy in 10 patients. All patients were subsequently treated with warfarin to maintain an International Normalized Ratio of 2.3 to 3.0.
Cardiac output was determined according to the Fick principle by measuring oxygen consumption with the Waters MRM-2 Oxygen Consumption Monitor. Assumed oxygen consumption was used to calculate cardiac output when patients were receiving supplemental oxygen, because direct measurement of oxygen consumption was not possible with our equipment. Thermodilution was not used to determine cardiac output because of the tricuspid insufficiency in all of these patients.
All survivors were followed up clinically and noninvasively through May 1994 (2 to 45 months after the blade balloon atrial septostomy). Eight patients underwent repeat cardiac catheterization 7 to 27 months after the procedure.
In all analyses, significance is defined as a two-tailed P<.05, and results are presented for the entire group of patients and, in some instances, for NYHA Class III and Class IV patients separately. Descriptive statistics presented include the mean±SD for hemodynamic and exercise data and the number of patients in a particular class for the qualitative variables (eg, NYHA class).
The time points considered in the analyses of the hemodynamic variables are baseline, immediately after blade balloon atrial septostomy, and follow-up catheterization. The time points considered in the analyses of the exercise variables are baseline, 2 weeks to 3 months after blade balloon atrial septostomy, and 9 to 15 months after septostomy. Pairwise differences between these time periods in hemodynamic and exercise variables are assessed by use of Student’s t test.
Survival was characterized by use of Kaplan-Meier curves for all 15 blade balloon atrial septostomy patients, for the 13 patients who survived the procedure, and for a historical control group consisting of 135 primary pulmonary hypertension patients in NYHA Class III or Class IV who were in the NIH Primary Pulmonary Hypertension Registry and who had received standard therapy (Table 2⇓).2 Because chronic anticoagulation has been shown to improve survival in patients with primary pulmonary hypertension,9 12 subgroup analysis was performed on a subset of this historical control group consisting of 31 patients whose standard therapy included warfarin anticoagulation (Table 2⇓). Differences in survival between the blade balloon atrial septostomy patients and each of the historical control groups were assessed by use of proportional hazards regression. The particular model stratifies patients according to NYHA class and uses a confounder score to control for baseline mean pulmonary artery pressure, mean right atrial pressure, and cardiac index, three variables shown to be associated with survival.3 Data from patients who underwent lung transplantation were censored at time of transplantation.
We also compared the probability of survival of the blade balloon atrial septostomy patients with their estimated probability of survival at 1, 2, and 3 years according to the equations developed from the NIH Primary Pulmonary Hypertension Registry data2 :
where x is mean pulmonary artery pressure, y is mean right atrial pressure, and z is cardiac index.
Thirteen patients survived the blade balloon atrial septostomy procedure and 2 died during cardiac catheterization. Patient 4 died as the long sheath was being advanced into the left atrium, and patient 15 died after the first blade incision, as a result of profound hypoxemia due to massive right-to-left shunting across the interatrial communication. Before the procedure, both patients had frequent episodes of syncope at rest, and were the only 2 patients on maximal cardiorespiratory support at the time of cardiac catheterization. Four patients died 5, 19, 28, and 38 months after the procedure. Patient 1 committed suicide; patients 2 and 7, who initially improved after septostomy, died because of disease progression; and patient 8 died after surgery for placement of a permanent intravenous catheter (Table 1⇑).
Table 1⇑ shows the outcome for the 13 survivors. Initially, 11 patients clinically improved and 2 remained unchanged. There was a significant improvement in the functional capacity of the survivors, as judged by a change in the mean NYHA functional class from Class 3.5±0.5 to Class 2.2±0.7 (P<.001). No patient experienced further syncope, and signs and symptoms of right heart failure (including ascites, peripheral edema, and hepatomegaly) improved in all 6 NYHA Class IV patients. There was no significant change in exercise tolerance (progressive cycle ergometry) at 2 weeks to 3 months (n=10) and 9 to 15 months (n=11) after blade balloon atrial septostomy. Exercise endurance, as defined by the 6-minute walk test, increased from 305±116 m before the procedure to 358±76 m at 2 weeks to 3 months after septostomy (n=7, P=.14). There was no change in exercise endurance at 9 to 15 months compared with before the procedure (n=6, P=.23). As of May 1994, 2 of the 9 long-term survivors (15 to 46 months; mean±SD, 32.7±10.0 months) underwent successful lung transplantation 15 and 20 months after blade balloon atrial septostomy, and 3 have been taken off the active transplantation list because of marked clinical improvement. Patient 13 began long-term continuous intravenous prostacyclin 18 months after septostomy and is still on the active transplantation list, although her condition is improved compared with before blade balloon atrial septostomy. The 3 additional survivors also remain clinically improved and are not candidates for transplantation.
Patient 7 developed hepatitis C, possibly related to transfusions at the time of the procedure, 4 months after blade balloon atrial septostomy. Patient 12 underwent repeat blade balloon atrial septostomy 6 months after the initial procedure because of closure of the interatrial communication. The second septostomy was performed without complications.
Hemodynamics before, immediately after, 24 hours after, and 7 to 27 months after blade balloon atrial septostomy are shown for each patient in Table 3⇓⇓ and summarized in Table 4⇓. There was no significant change in mean pulmonary artery pressure, mean systemic arterial pressure, or mean right atrial pressure immediately after the procedure (Figs 1⇓ and 2⇓). Mean left atrial pressure increased from 4.8±2.6 to 7.3±2.8 mm Hg (P<.05) immediately after the procedure (Fig 2⇓). Within 24 hours after the procedure, systemic arterial oxygen saturation fell from 98±2% to 85±6% (n=10, P<.05) (Fig 3⇓), and cardiac index increased from 2.1±0.7 to 3.9±1.1 L · min−1 · m−2 (n=10, P<.05) (Fig 4⇓), resulting in an increase in systemic oxygen transport from 418±128 to 661±213 mL O2 · min−1 · m−2 (n=10, P<.05) (Fig 5⇓).
Eight patients underwent repeat cardiac catheterization 7 to 27 months (mean, 18 months) after blade balloon atrial septostomy. Compared with the data obtained before and immediately after the procedure, there was no significant change in mean pulmonary artery pressure or mean systemic arterial pressure (Fig 1⇑). Mean right atrial pressure, which had remained unchanged immediately after septostomy, fell from 10.1±5.2 to 6.1±6.9 mm Hg (n=8, P<.15 compared with baseline) (Fig 2⇑). Left atrial pressure, which had increased immediately after septostomy, remained higher (5.0±2.7 compared with 7.0±2.0 mm Hg; n=8, P<.10 compared with baseline) (Fig 2⇑). At follow-up catheterization, systemic arterial oxygen saturation remained decreased compared with baseline (91.0±6.9% and 97.6±2.0%, respectively; n=7, P<.05) and cardiac index remained significantly higher (4.3±1.7 compared with 2.3±0.6 L · min−1 · m−2; n=7, P<.05), resulting in an increase in systemic oxygen transport from 450±107 mL O2 · min−1 · m−2 at baseline to 757±325 mL O2 · min−1 · m−2 at follow-up catheterization (n=7, P<.10) (Figs 3 through 5⇑⇑⇑).
Three NYHA Class IV patients underwent repeat cardiac catheterization 18, 21, and 27 months after septostomy. Compared with before septostomy, there was a significant fall in mean right atrial pressure from 14.7±3.5 to 4.3±1.5 mm Hg (n=3, P<.05) and a significant increase in cardiac index from 2.1±0.7 to 6.1±0.9 L · min−1 · m−2 (n=3, P<.05).
As shown in Fig 6⇓, there was a trend toward improved long-term survival in all patients who underwent blade balloon atrial septostomy compared with historical control subjects who received standard therapy (NIH Registry; n=135, P=.07) and control subjects whose standard therapy included chronic anticoagulation therapy (NIH Registry; n=31, P=.08).2 In the 13 patients who survived the procedure, there was improved long-term survival compared with historical control subjects who received standard therapy (NIH Registry; n=135, P=.01) and control subjects whose standard therapy included chronic anticoagulation therapy (NIH Registry; n=31, P=.04).2
The 1-, 2-, and 3-year survival rates for the blade balloon atrial septostomy patients were 80%, 73%, and 65%, respectively, compared with 64%, 51%, and 41% for the entire group of NYHA Class III and Class IV NIH Registry patients treated with standard therapy (P=.07) and with 77%, 52%, and 41% for the 31 NYHA Class III and Class IV NIH Registry patients whose standard therapy included warfarin anticoagulation (P=.08). Blade balloon atrial septostomy significantly improved survival for patients in the present study compared with the 1-, 2-, and 3-year survival rates (62%, 48%, and 39%) predicted by the equation developed from the NIH Primary Pulmonary Hypertension Registry data2 (P<.05).
Patients with primary pulmonary hypertension who have recurrent syncope, severe right heart failure, or both have a poor prognosis.1 2 3 We have previously reported that patients with primary pulmonary hypertension and recurrent syncope do not have an adequate patent foramen ovale.13 It is probable that patients with pulmonary vascular disease and an intact interatrial septum experience syncope with exercise because of systemic vasodilatation and an inability to augment cardiac output to maintain cerebral perfusion pressure. Longer survival has been described in patients with primary pulmonary hypertension who have an interatrial communication.4 With sufficient right-to-left shunting through an interatrial communication, cardiac output can be maintained or increased as needed, despite severe pulmonary vascular disease. Furthermore, right-to-left shunting at the atrial level allows decompression of the right atrium and right ventricle, alleviating signs and symptoms of right heart failure. These hemodynamics are associated with decreased systemic arterial saturation but improved oxygen transport.
The importance of a patent foramen ovale in patients with pulmonary vascular disease was recently questioned by Nootens et al.14 In their study, a patent foramen ovale was defined solely by demonstration of right-to-left shunting by transesophageal echocardiography. However, patency of the foramen ovale is most likely beneficial only if it allows sufficient right-to-left shunting to maintain cardiac output, as is evidenced by significant systemic arterial oxygen desaturation at rest or during exercise. We therefore defined a patent foramen ovale as adequate if the two-dimensional echocardiogram with cavitation study demonstrated right-to-left shunting at the atrial level and if the patient, fully saturated at rest, desaturated with exercise because of right-to-left atrial shunting. Nootens et al did not address this issue and therefore may have underestimated the beneficial value of an adequate interatrial communication.
Previous studies have shown that blade balloon atrial septostomy can be successfully performed in patients with advanced pulmonary vascular disease and can bring about variable clinical improvement.6 7 15 Our study demonstrates that blade balloon atrial septostomy results in significant clinical and hemodynamic improvement in patients with primary pulmonary hypertension who have recurrent syncope and right heart failure. No patient in the present study experienced further syncope, and signs and symptoms improved in all patients with right heart failure. There was no change in measured exercise tolerance at 2 weeks to 3 months or at 9 to 15 months after septostomy. In contrast to recently published data that showed worsening exercise endurance (6-minute walk test) over 12 weeks in patients with severe primary pulmonary hypertension on conventional therapy,16 our data showed a trend towards improvement in our patients after blade balloon atrial septostomy, compared with baseline, at 2 weeks to 3 months, without deterioration at 9 to 15 months. Although systemic arterial oxygen saturation decreased, oxygen delivery and cardiac output improved after the procedure because of right-to-left shunting at the atrial level.
In addition to symptomatic improvement, which has been described by others,7 15 our study demonstrated a trend toward improved survival in patients with severe primary pulmonary hypertension who underwent blade balloon atrial septostomy. Although blade balloon atrial septostomy does not alter the underlying disease process of primary pulmonary hypertension, the right-to-left shunt and resultant increase in cardiac output are also associated with an improved quality of life for patients with severe primary pulmonary hypertension. In addition, patients with severe primary pulmonary hypertension who were not previously considered candidates for acute vasodilator drug testing on the basis of risk-benefit considerations10 may become appropriate candidates for acute drug testing after they have clinically improved following blade balloon atrial septostomy.
Currently, we consider patients with primary pulmonary hypertension for blade balloon atrial septostomy if they have recurrent syncope despite maximal medical therapy, including oral calcium-channel blockers or continuous intravenous prostacyclin. In addition, blade balloon atrial septostomy is considered for patients with recurrent syncope and severe right heart failure who are not candidates for acute vasodilator drug testing because of the high mortality predicted on the basis of poor performance on exercise testing.10
Blade balloon atrial septostomy is contraindicated in patients with severe right heart failure on maximal cardiorespiratory support. Patients with severe right heart failure and markedly elevated pulmonary vascular resistance do not tolerate atrial septostomy, because massive right-to-left shunting may result in insufficient pulmonary blood flow and severe hypoxemia.
Because of the procedure-related mortality, precautions must be taken to minimize the risks of cardiac catheterization. Patients with primary pulmonary hypertension have little or no cardiopulmonary reserve, so they may not tolerate the several months needed to increase their hemoglobin and hematocrit in response to the decrease in systemic arterial oxygen saturation after blade balloon atrial septostomy. Therefore, to maintain oxygen delivery after septostomy, the hematocrit should be increased by either transfusion of packed red blood cells or pretreatment with erythropoietin so oxygen content is maintained in the normal range. Patients must be sedated before the procedure to prevent anxiety but not to the degree that respiratory drive is depressed. Patients should be on supplemental oxygen during cardiac catheterization. In addition, if there are signs of right ventricular dysfunction, additional inotropic support should be initiated before the procedure to optimize cardiac function. Patients should be well hydrated to maintain adequate right heart filling pressures after creation of the atrial communication. This may require additional volume expansion before or during the cardiac catheterization so right atrial pressure does not decrease abruptly, because sufficient right ventricular filling and pulmonary blood flow need to be maintained.
With clinical and hemodynamic improvement, and improved survival in selected patients after septostomy, blade balloon atrial septostomy may be particularly useful as a palliative bridge to transplantation. There are approximately 1300 patients awaiting lung or heart-lung transplantation in the United States, and the current estimated waiting time for lung transplantation is approximately 1 year and for heart-lung transplantation more than 18 months.17 Current experience has been that 30% to 40% of patients with primary pulmonary hypertension who are awaiting transplantation will die before a suitable donor organ is available (L.J. Rubin, MD, personal communication, 1994). Blade balloon atrial septostomy may be particularly useful, along with other treatment modalities, in sustaining seriously ill patients awaiting transplantation. In some patients, transplantation can be deferred for several years because of prolonged survival with an improved quality of life.
The authors thank Margaret Challenger, Robert Garofano, MS, EdM, and Jillian Kirkpatrick, RN, for their assistance in the study, and all the physicians and nurses who participated in the care of our patients.
- Received December 27, 1993.
- Revision received October 26, 1994.
- Accepted November 6, 1994.
- Copyright © 1995 by American Heart Association
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