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Eur J Cardiothorac Surg 2004;26:66-72
© 2004 Elsevier Science NL

Coronary flow characteristics after a Bentall procedure with or without sinuses of Valsalva

Cattedra di Cardiochirurgia, Università di Roma Tor Vergata, European Hospital, via Portuense 700, 00149 Roma, Italy

Received 10 October 2003; received in revised form 2 March 2004; accepted 6 April 2004.

^* Corresponding author. Tel.: +39-06-659-759; fax: +39-06-659-757-24
e-mail: depauli{at}tin.it

	Abstract

Top Abstract 1. Introduction 2. Patients and methods 3. Results 4. Discussion Appendix A. Conference... References

 
Objectives: The sinuses of Valsalva are known to contribute to the normal function of the aortic valve. Little is known about their role in promoting coronary artery blood flow. The aim of this study was to compare coronary artery flow characteristics among patients undergoing a Bentall operation by means of a conventional cylindrical Dacron conduit or with a new conduit with pseudosinuses of Valsalva or in patients retaining their natural sinuses of Valsalva after aortic valve and supracoronary ascending aorta replacement. Methods: One year after a Bentall procedure with a standard cylindrical Dacron conduit (7 patients, group A) or with the new conduit (7 patients, group B), or after aortic valve and ascending aortic replacement (control group, 7 patients, group C) coronary flow velocity reserve and diastolic to systolic time integral ratio at baseline and after maximal hyperemia (with 40 µg of adenosine) were assessed by using a 0.014-in. Doppler guidewire positioned in the middle portion of the left anterior descending coronary artery. All patients were in NYHA class I, sinus rhythm and free of coronary disease. Results: Arterial blood pressures and heart rate were comparable among groups. Intracoronary Doppler measurements did not show any significant difference in coronary vascular reserve between the three groups (3.6±0.4 vs 3.1±0.7 vs 3.7±0.5, P=0.2). A greater diastolic component at baseline was present in group B patients (5.5±1.9 vs 3.5±0.9 in group A and 3.7±0.9 in group C, P=0.024). After maximal hyperemia the diastolic component increased slightly in group A patients (8%) while both in groups B and C significantly decreased (–15 and –20%, respectively) (P=0.017). Conclusions: The presence of pseudosinuses of Valsalva does not influence coronary flow reserve. After maximal coronary vasodilation the increase in the systolic component of coronary flow is more evident in the presence of sinuses or pseudosinuses of Valsalva, thus suggesting that coronary flow pattern may be affected by the presence of sinuses.

Key Words: Coronary flow • Bentall procedure • Sinuses of Valsalva • Dacron graft • Eddy currents

	1. Introduction

Top Abstract 1. Introduction 2. Patients and methods 3. Results 4. Discussion Appendix A. Conference... References

 
The sinuses of Valsalva are of paramount importance in assuring normal function of the aortic valve. Their particular shape and distensibility along with the presence of the sinotubular junction regulates the opening and closing characteristics of the aortic valve [1,2]. The eddy currents that are formed inside the sinuses act as a cushion preventing any systolic impact of the leaflet with the aortic wall. Furthermore, they promote valve closure already before the end of systole in a way that, when the flow is reversed during diastole, leaflet excursion is reduced and valve closure is smooth and synchronous. The anatomical unit formed by the sinus and the valve leaflet is important in sharing the diastolic stress on the leaflet and reducing stress concentration at any point [3]. Surgical reconstruction of the aortic root that abolish or alter the shape of the aortic sinuses should be avoided if a long-term durability of the leaflet is desired.

Coronary arteries are positioned at the bottom of the coronary sinuses but little is known on the role of the sinuses in promoting coronary blood flow (CBF). The aim of this study was to evaluate coronary flow characteristics with or without the presence of sinuses of Valsalva in order to verify the hypothesis that the sinuses of Valsalva might somehow modulate the coronary flow pattern.

We recently developed a modified tube graft that incorporates pseudosinuses of Valsalva (Gelweave Valsalva^TM, Terumo Vascutek, Renfrewshire, Scotland UK) and facilitates an anatomical reconstruction of the aortic root [4]. Therefore, we evaluated coronary flow characteristics in patients after a Bentall procedure with a conventional cylindrical graft that completely abolish the sinuses, after a Bentall procedure with the conduit that incorporates pseudosinuses of Valsalva and compared the results with a group of patients retaining their natural sinuses after aortic valve and supracoronary ascending aorta replacement.

	2. Patients and methods

Top Abstract 1. Introduction 2. Patients and methods 3. Results 4. Discussion Appendix A. Conference... References

 
2.1. Patient population
Among all patients undergoing surgical procedure on the aortic valve and ascending aorta at our institution more than 1 year before the present investigation we selected 21 consecutive patients that formed the basis of this study. Seven patients had undergone a Bentall procedure by means of a standard Dacron conduit (group A; absence of sinuses, Fig. 1a) , 7 patients had undergone a Bentall procedure by means of a modified Dacron graft incorporating sinuses of Valsalva (group B; pseudosinuses, Fig. 1b), and 7 patients had undergone aortic valve replacement associated with a supracoronary Dacron graft replacement (group C; natural sinuses, Fig. 1c). In order to avoid possibly confounding effects, patients were selected on the basis of the size of Dacron graft and the type of prosthetic aortic valve. Furthermore, only patients with normal cardiac function, sinus rhythm and absence of coronary disease were considered. Patient characteristics are summarized in Table 1 . All patients gave written informed consent for participation in the study, which was approved by the Institutional Ethics Committee.

View larger version (60K): [in this window] [in a new window]   Fig. 1. Postoperative angiographic images of the three study groups. (a) Patients who underwent Bentall operation with a standard straight graft (group A); (b) patients who underwent Bentall operation with the modified conduit incorporating sinuses of Valsalva (group B); (c) patients who underwent aortic valve replacement associated with supracoronary aortic replacement (group C).

The modified graft design has been more extensively described in previous articles [4,5]. Briefly, it has a short proximal portion (the skirt of the graft) that stretches horizontally upon conduit pressurization allowing the recreation of pseudosinuses of Valsalva. This modified graft has been successfully employed in valve sparing procedure [6,7] where it contributes to an anatomical reconstruction of the aortic root. Given its peculiar design it has also been employed for Bentall procedure where it facilitates coronary anastomosis and avoids or reduces any undue tension on the coronary ostia (Fig. 2) .

View larger version (128K): [in this window] [in a new window]   Fig. 2. Artistic drawing of the modified Valsalva Dacron conduit in a Bentall configuration showing the improved adaptability with respect to the coronary buttons.

2.4. Statistical analysis
A two-way analysis of variance was used to compare hemodynamic, anatomical, and Doppler derived data between the three groups, with the Scheffé F test for post hoc multiple comparisons. Categorical data were compared using the ² test. A P-value <0.05 was considered significant. All data are expressed as mean value±standard deviation. All statistical analysis was performed with StatView (version 5.0) for Windows 8.0 (SAS Institute Inc.).

	3. Results

Top Abstract 1. Introduction 2. Patients and methods 3. Results 4. Discussion Appendix A. Conference... References

 
All patients were asymptomatic and in NYHA class I at the time of evaluation. Echocardiographic evaluation showed normal left ventricular diameter and ventricular function (Table 2) . Arterial blood pressure and heart rate at the time of evaluation were comparable between the three groups at baseline and throughout the study (Table 3) .

View larger version (123K): [in this window] [in a new window]   Fig. 3. Typical intracoronary Doppler tracings at baseline and after maximal hyperemia with a 20 µg bolus injection of adenosine from a patient of each study group. (a) Absence of sinuses (standard straight graft, group A); (b) pseudosinuses (conduit incorporating sinuses of Valsalva, group B); (c) natural sinuses (aortic valve replacement associated with supracoronary aortic replacement, group C).

	4. Discussion

Top Abstract 1. Introduction 2. Patients and methods 3. Results 4. Discussion Appendix A. Conference... References

In the last years we developed a modified vascular prosthesis that allows a more anatomical reconstruction of the aortic root in valve sparing operation. It has been successfully used either in the remodeling [6] or in the reimplantation type of valve sparing procedure [7] with valve motion characteristics that are more similar to healthy individuals. Given its peculiar anatomical shape it has also been applied in cases of Bentall procedure [4,5] where it is thought to facilitate coronary anastomosis and at the same time to decrease tension upon the coronary buttons during surgery or after conduit pressurization. In particular, the cyclic movement of the heart is not directly transmitted to the coronary anastomosis but the reconstructed root follows the heartbeat as a single functional unit avoiding stress concentration at any given point. As a consequence, a reduction in the incidence of late pseudoaneurysm formation is to be expected. Interestingly enough, the button technique of coronary reimplantation has gained popularity over the inclusion technique because it reduces tension, bleeding and pseudoaneurysm formation [8].

Even though in the case of Bentall operation this new vascular prosthesis does not reproduce three independent sinuses but rather a single large egg-shaped proximal portion (Fig. 2), it still generates vortices within. Interestingly, the presence of this portion of the graft that expands horizontally to reconstruct the aortic root offers the possibility of investigating the physiological role, if present, that the sinuses might have in regulating CBF. Patients receiving a Bentall procedure with a standard cylindrical Dacron graft have normal hemodynamic parameters and normal myocardial perfusion but little is known about the effect that the lack of sinuses of Valsalva might have on the CBF at rest or under effort.

It has been shown that reduced diastolic perfusion along with increased extravascular compression is the main cause of coronary microcirculation dysfunction in patients with aortic stenosis. The anginal symptoms in patients with aortic stenosis and normal coronary arteries can therefore be explained by a reduced coronary vasodilator reserve [9,10]. Furthermore, more recently Rajappan et al. [11] found that the improvement of myocardial blood flow after aortic valve replacement for aortic stenosis is the effect of the increase in diastolic perfusion time. Therefore, diastolic perfusion time is to be considered a main factor in the regulation of myocardial perfusion. Our hypothesis was that the presence of sinuses of Valsalva (group C patients) could somehow participate in the regulation of coronary flow pattern during the cardiac cycle. Although the coronary flow reserve was normal in all patient groups, we found that patients whose sinuses were abolished by the surgical procedure (group A patients) did not significantly modify the diastolic/systolic ratio after maximal hyperemic vasodilation. Conversely, patients with their natural sinuses showed the ability to increase their systolic component. In particular, patients whose sinuses were replaced by some sort of pseudosinuses (group B patients) showed modification in D/S ratio similar to patients with natural sinuses. Interestingly, their diastolic component at baseline was significantly higher than the other patients groups. The reason for the higher diastolic component at baseline in group B patients compared to group C, despite the fact that in both groups sinuses are present, might be either due to the single circumferential sinus in group B or to a difference in sinuses elasticity. Nevertheless, our findings seem to suggest that aortic sinuses (or pseudosinuses) may represent one of the multiple components responsible for CBF regulation especially in patients with myocardial hypertrophy in whom resting coronary flow is increased.

It has also been demonstrated that the reverse of flow necessary to close a prosthetic mechanical valve along with the leakage flow combine to create a disturbed flow inside the sinuses of Valsalva [12,13]. Kleine et al. [14] recently demonstrated that varying the orientation of a prosthetic mechanical valve has a significant impact on CBF. In particular they found that, for a given valve, varying from the best orientation (the one giving the lowest pressure gradients and the lowest downstream turbulence) to the worst orientation causes a major and significant reduction in CBF. This finding support the hypothesis of a direct correlation between the low turbulence in the aortic root and a high diastolic coronary flow rate. Therefore, even when the valve is closed, disturbance of aortic root flow pattern seems to play a role in determining an optimal diastolic CBF. Based on these findings, it is also possible that the shape of the aortic root and in particular the presence or the absence of sinuses of Valsalva, by regulating the amount and direction of vortices in the aortic root would also influence the coronary flow pattern. In our study groups all patients had their bileaflet mechanical valve implanted with one orifice facing the right cusp (usually considered the best orientation with respect to flow hemodynamics) while the biological valves were almost equally distributed between the three groups (Table 1). In this way we sought to keep all possible influencing variables to a minimum in order to isolate the effect of the aortic root shape on the coronary flow. Finally, the reason for the increase of the systolic component during adenosine-induced hyperemia in patients retaining their coronary sinuses cannot be deduced by the results of our study. It might only be speculated that a maximal vasodilation induced by adenosine at the coronary arterioles could further enhance myocardial perfusion during systole in patients with preserved or recreated vortices inside the aortic root. However, this intriguing finding deserves further investigation, i.e. comparison of coronary flow pattern after adenosine-induced increase in CBF with pacing-induced increase in CBF.

	Footnotes

 
Presented at the joint 17th Annual Meeting of the European Association for Cardio-thoracic Surgery and the 11th Annual Meeting of the European Society of Thoracic Surgeons, Vienna, Austria, October 12–15, 2003.

	Appendix A. Conference discussion

Top Abstract 1. Introduction 2. Patients and methods 3. Results 4. Discussion Appendix A. Conference... References

 
Dr M. Turina (Zurich, Switzerland): I would like to congratulate you for introducing this subject, because this type of graft exists for a number of years and nobody knows if it is useful or if it is really deleterious.

Now, looking at your data, did you try to standardize the data with respect to a left ventricular end-diastolic dimension and the left ventricular muscle mass? Because if they are different, the wall tension will be different and this could explain some of the differences.

Dr De Paulis: Yes. I didn't report, for the sake of time, the complete measurements. However, at the time of the Doppler evaluation, one year after the operation all patients underwent echocardiography. All end-diastolic and systolic volumes were reduced with no significant difference between patient groups. Similarly, the mass was decreased. Mass and volumes were both decreased and no difference between the three groups were found.

Dr R. Poston (Baltimore, MD, USA): Is there any evidence that the diastolic/systolic flow ratio matters or impacts patient outcome? Coronary flow reserve is an important concept that relates to outcome. But it seems that the other more intricate parameters that you reported were ‘mined’ out of your data and have no clinical value.

Dr De Paulis: I don't think that the diastolic/systolic ratio will make any difference from a clinical point of view. I was only trying to find out if the presence of the sinus would somehow modulate the pattern of coronary flow. I don't know about the clinical significance. In normal condition, is probably not significant. However, we have to imagine that some minor physiological finding could be clinically relevant in more extreme cases, like in the presence of increased ventricular mass before mass regression, or for instance, at the moment of maximal stress. But at the moment, I do not have an answer. I don't know how this difference in coronary flow pattern could somehow be transferred to the clinical situation.

	References

Top Abstract 1. Introduction 2. Patients and methods 3. Results 4. Discussion Appendix A. Conference... References

 

1. Vesely I. Aortic root dilation prior to valve opening explained by passive hemodynamics. J Heart Valve Dis 2000;9:16-20.[Medline]
2. Thubrikar M., Bosher P.L., Nolan S.P. The mechanism of opening of the aortic valve. J Thorac Cardiovasc Surg 1979;77:863-870.[Abstract]
3. Thubrikar M.J., Nolan S.P., Aouad J., Deck D. Stress sharing between the sinus and leaflets of canine aortic valve. Ann Thorac Surg 1986;42(4):434-440.[Abstract]
4. De Paulis R., De Matteis G.M., Nardi P., Scaffa R., Colella D., Chiariello L. A new aortic Dacron conduit for surgical treatment of aortic root pathology. Ital Heart J 2000;1(7):457-463.[Medline]
5. De Paulis R., De Matteis G.M., Nardi P., Scaffa R., Colella D.F., Bassano C., Tomai F., Chiariello L. One year appraisal of a new aortic root conduit with sinuses of Valsalva. J Thorac Cardiovasc Surg 2002;123:33-39.[Abstract/Free Full Text]
6. De Paulis R., De Matteis G.M., Nardi P., Scaffa R., Buratta M., Chiariello L. Opening and closing characteristics of the aortic valve after valve sparing procedures using a new aortic root conduit. Ann Thorac Surg 2001;72:487-494.[Abstract/Free Full Text]
7. De Paulis R., De Matteis G.M., Nardi P., Scaffa R., Bassano C., Chiariello L. Analysis of valve motion after the reimplantation type of valve sparing procedure (David I) with a new aortic root conduit. Ann Thorac Surg 2002;74:53-57.[Abstract/Free Full Text]
8. Kawaze K., Eishi K., Kawashima Y. New modified Bentall procedure: Carrel patch and inclusion technique. Ann Thorac Surg 1993;55:1578-1579.[Abstract]
9. Choudhury L., Rosen S.D., Patel D., Nihoyannopoulos P., Camici P.G. Coronary vasodilator reserve in primary and secondary left ventricular hypertrophy: a study with positron emission tomography. Eur Heart J 1997;18:108-116.[Abstract/Free Full Text]
10. Rajappan K., Rimoldi O., Dutka D.P., Ariff B., Pennell D.J., Sheridan D., Camici P.G. Mechanism of coronary microcirculatory dysfunction in patients with aortic stenosis and angiographically normal coronary arteries. Circulation 2002;105:470-476.[Abstract/Free Full Text]
11. Rajappan K., Rimoldi O., Camici P.G., Bellenger N.G., Pennell D.J., Sheridan D.J. Functional changes in coronary microcirculation after valve replacement in patients with aortic stenosis. Circulation 2003;107:3170-3175.[Abstract/Free Full Text]
12. Bodnar E., Reul H., Schmitz B. Prosthetic valve function under simulated low cardiac output conditions: preliminary observations. J Heart Valve Dis 1993;2:348-351.[Medline]
13. Yoganathan A.P., Chaux A., Gray R.J., Woo Y.R., De Robertis M., Williams F.P., Matloff J.M. Bileaflet, tilting disc and porcine aortic valve substitutes: in vitro hydrodynamic characteristics. J Am Coll Cardiol 1984;3:313-320.[Abstract]
14. Kleine P., Scherer M., Abdel-Rahman U., Klesius A.A., Ackerman H., Moritz A. Effects of mechanical aortic valve orientation on coronary artery flow: comparison of tilting disc versus bileaflet prostheses in pigs. J Thorac Cardiovasc Surg. 2002;124:925-932.[Abstract/Free Full Text]

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