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A modelling study of atrial septostomy for pulmonary arterial hypertension, and its effect on the state of tissue oxygenation and systemic blood flow

Published online by Cambridge University Press:  10 February 2010

Gerhard-Paul Diller*
Affiliation:
National Heart and Lung Institute, Imperial College of Science and Medicine, London, UK Adult Congenital Heart Unit, Royal Brompton Hospital, London, UK
Astrid E. Lammers
Affiliation:
Paediatric Cardiology, Great Ormond Street Hospital for Children, London, UK Institute of Child Health, University College London, UK
Sheila G. Haworth
Affiliation:
Paediatric Cardiology, Great Ormond Street Hospital for Children, London, UK Institute of Child Health, University College London, UK
Konstantinos Dimopoulos
Affiliation:
National Heart and Lung Institute, Imperial College of Science and Medicine, London, UK Adult Congenital Heart Unit, Royal Brompton Hospital, London, UK
Graham Derrick
Affiliation:
Paediatric Cardiology, Great Ormond Street Hospital for Children, London, UK
Philipp Bonhoeffer
Affiliation:
Paediatric Cardiology, Great Ormond Street Hospital for Children, London, UK
Michael A. Gatzoulis
Affiliation:
National Heart and Lung Institute, Imperial College of Science and Medicine, London, UK Adult Congenital Heart Unit, Royal Brompton Hospital, London, UK
Darrel P. Francis
Affiliation:
National Heart and Lung Institute, Imperial College of Science and Medicine, London, UK International Centre for Circulatory Health, Imperial College of Science and Medicine, London, UK
*
Correspondence to: Dr Gerhard-Paul Diller, Adult Congenital Heart Centre and Centre for Pulmonary Hypertension, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK. Tel: +44 207 351 8602; Fax: +44 207 351 8629; E-mail: [email protected]

Abstract

Atrial septostomy is performed in patients with severe pulmonary arterial hypertension, and has been shown to improve symptoms, quality of life and survival. Despite recognized clinical benefits, the underlying pathophysiologic mechanisms are poorly understood. We aimed to assess the effects of right-to-left shunting on arterial delivery of oxygen, mixed venous content of oxygen, and systemic cardiac output in patients with pulmonary arterial hypertension and a fixed flow of blood to the lungs. We formulated equations defining the mandatory relationship between physiologic variables and delivery of oxygen in patients with right-to-left shunting. Using calculus and computer modelling, we considered the simultaneous effects of right-to-left shunting on physiologies with different pulmonary flows, total metabolic rates, and capacities for carrying oxygen. Our study indicates that, when the flow of blood to the lungs is fixed, increasing right-to-left shunting improves systemic cardiac output, arterial blood pressure, and arterial delivery of oxygen. In contrast, the mixed venous content of oxygen, which mirrors the average state of tissue oxygenation, remains unchanged. Our model suggests that increasing the volume of right-to-left shunting cannot compensate for right ventricular failure. Atrial septostomy in the setting of pulmonary arterial hypertension, therefore, increases the arterial delivery of oxygen, but the mixed systemic saturation of oxygen, arguably the most important index of tissue oxygenation, stays constant. Our data suggest that the clinically observed beneficial effects of atrial septostomy are the result of improved flow of blood rather than augmented tissue oxygenation, provided that right ventricular function is adequate.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 2010

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Footnotes

*

These authors contributed equally to this manuscript.

References

1.D’Alonzo, GE, Barst, RJ, Ayres, SM, Bergofsky, EH, Brundage, BH, Detre, KM, Fishman, AP, Goldring, RM, Groves, BM, Kernis, JTL. Survival in patients with primary pulmonary hypertension. Results from a national prospective registry. Ann Intern Med. 1991; 115: 343349.CrossRefGoogle ScholarPubMed
2.Kerstein, D, Levy, PS, Hsu, DT, Hordof, AJ, Gersony, WM, Barst, RJ. Blade balloon atrial septostomy in patients with severe primary pulmonary hypertension. Circulation 1995; 91: 20282035.CrossRefGoogle ScholarPubMed
3.Micheletti, A, Hislop, AA, Lammers, A, Bonhoeffer, P, Derrick, G, Rees, P, Haworth, SG. Role of atrial septostomy in the treatment of children with pulmonary arterial hypertension. Heart 2006; 92: 969972.CrossRefGoogle ScholarPubMed
4.Klepetko, W, Mayer, E, Sandoval, J, Trulock, EP, Vachiery, JL, Dartevelle, P, Pepke-Zaba, J, Jamieson, SW, Lang, I, Corris, P. Interventional and surgical modalities of treatment for pulmonary arterial hypertension. J Am Coll Cardiol 2004; 43: 73S80S.CrossRefGoogle ScholarPubMed
5.Sun, X-G, Hansen, JE, Oudiz, RJ, Wasserman, K. Exercise pathophysiology in patients with primary pulmonary hypertension. Circulation 2001; 104: 429435.CrossRefGoogle ScholarPubMed
6.Webb, G, Gatzoulis, MA. Atrial septal defects in the adult: recent progress and overview. Circulation 2006; 114: 16451653.CrossRefGoogle ScholarPubMed
7.Rothman, A, Sklansky, MS, Lucas, VW, Kashani, IA, Shaughnessy, RD, Channick, RN, Auger, WR, Fedullo, PF, Smith, CM, Kriett, JM, Jamieson, SW. Atrial septostomy as a bridge to lung transplantation in patients with severe pulmonary hypertension. The American Journal of Cardiology 1999; 84: 682686.CrossRefGoogle ScholarPubMed
8.Rich, MDS, Dodin, MDE, McLaughlin, MDVV. Usefulness of atrial septostomy as a treatment for primary pulmonary hypertension and guidelines for its application. The American Journal of Cardiology 1997; 80: 369371.CrossRefGoogle ScholarPubMed
9.Sandoval, J, Gaspar, J, Pulido, T, Bautista, E, Martinez-Guerra, ML, Zeballos, M, Palomar, A, Gomez, A. Graded balloon dilation atrial septostomy in severe primary pulmonary hypertension. A therapeutic alternative for patients nonresponsive to vasodilator treatment. J Am Coll Cardiol 1998; 32: 297304.CrossRefGoogle ScholarPubMed
10.Thanopoulos, BD, Georgakopoulos, D, Tsaousis, GS, Simeunovic, S. Percutaneous balloon dilatation of the atrial septum: immediate and midterm results. Heart 1996; 76: 502506.CrossRefGoogle ScholarPubMed
11.Law, MA, Grifka, RG, Mullins, CE, Nihill, MR. Atrial septostomy improves survival in select patients with pulmonary hypertension. Am Heart J 2007; 153: 779784.CrossRefGoogle ScholarPubMed
12.Berman, EB, Barst, RJ. Eisenmenger’s syndrome: current management. Prog Cardiovasc Dis 2002; 45: 129138.CrossRefGoogle ScholarPubMed
13.Santamore, W, Barnea, O, Riordan, C, Ross, M, Austin, E. Theoretical optimisation of pulmonary-to-systemic flow ratio after a bidirectional cavopulmonary anastomosis. Am J Physiol 1998; 274: H694H700.Google Scholar
14.Hayes, MA, Timmins, AC, Yau, EH, Palazzo, M, Hinds, CJ, Watson, D. Elevation of systemic oxygen delivery in the treatment of critically ill patients. The New England Journal Of Medicine 1994; 330: 17171722.CrossRefGoogle ScholarPubMed
15.Diller, GP, Uebing, A, Willson, K, Davies, LC, Dimopoulos, K, Thorne, SA, Gatzoulis, MA, Francis, DP. Analytical identification of ideal pulmonary-systemic flow balance in patients with bidirectional cavopulmonary shunt and univentricular circulation: oxygen delivery or tissue oxygenation? Circulation 2006; 114: 12431250.CrossRefGoogle ScholarPubMed
16.Francis, DP, Willson, K, Thorne, SA, Davies, LC, Coats, AJ. Oxygenation in patients with a functionally univentricular circulation and complete mixing of blood: are saturation and flow interchangeable? Circulation 1999; 100: 21982203.CrossRefGoogle ScholarPubMed
17.Rossi, AF, Sommer, RJ, Lotvin, A, Gross, RP, Steinberg, LG, Kipel, G, Golinko, RJ, Griepp, RB. Usefulness of intermittent monitoring of mixed venous oxygen saturation after stage I palliation for hypoplastic left heart syndrome. Am J Cardiol 1994; 73: 11181123.CrossRefGoogle Scholar
18.Mathew, RJ. Postural syncope and autoregulation of cerebral blood flow. Biol Psychiatry 1996; 40: 923926.CrossRefGoogle ScholarPubMed
19.Schumacker, PT, Cain, SM. The concept of a critical oxygen delivery. Intensive Care Med 1987; 13: 223229.CrossRefGoogle ScholarPubMed
20.Broberg, CS, Bax, BE, Okonko, DO, Rampling, MW, Bayne, S, Harries, C, Davidson, SJ, Uebing, A, Khan, AA, Thein, S, Gibbs, JS, Burman, J, Gatzoulis, MA. Blood viscosity and its relationship to iron deficiency, symptoms, and exercise capacity in adults with cyanotic congenital heart disease. J Am Coll Cardiol 2006; 48: 356365.CrossRefGoogle ScholarPubMed
21.Diller, GP, Dimopoulos, K, Broberg, CS, Kaya, MG, Naghotra, US, Uebing, A, Harries, C, Goktekin, O, Gibbs, JS, Gatzoulis, MA. Presentation, survival prospects, and predictors of death in Eisenmenger syndrome: a combined retrospective and case-control study. Eur Heart J 2006; 27: 17371742.CrossRefGoogle ScholarPubMed
22.Little, RC, Opdyke, DF, Hawley, JG. Dynamics of experimental atrial septal defects. Am J Physiol 1949; 158: 241250.CrossRefGoogle ScholarPubMed
23.Mitsuru, F, Junichiro, F, Yoshiharu, U, Kohji, U, Kenji, S. Effect of increase in heart rate on interatrial shunt in atrial septal defect. Pediatric Cardiology 1992; V13: 146151.Google Scholar