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Prevention of left ventricular thrombus formation during pneumatic pump assist
Surgery, Vol. 3, No. 1, pp. 84-86, 1995 Copyright 0 1995 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0967-2109/95 $10.00 + 0.00
Cardiovascular
Prevention of left ventricular thrombus formation during pneumatic pump assist T. Sakamoto,T. Maruyama,T. Sugano,H. AraiandA. Suzuki Department of Cardiothoracic Surgery, School of Medicine, Tokyo Medical and Dental University, f-5-45, Yishima, Bun&vo-ku, Tokyo, I 1.3 Japan A postcardiotomy patient with a pneumatic pulsatile pump for left ventricular assist showed a smoke-like swirling echo within the left ventricle during pump assist. The image disappeared partially during intra-aortic balloon pumping, which was performed as usual. Subsequently, three pumps (native left ventricle, pneumatic and intra-aortic balloon) were driven synchronously: that is, the ventricular assist pump ejected the blood in the first half of the diastole of the native heart beat, and the intra-aortic balloon was inflated during the second half. With this bisected diastolic driving, the abnormal echo disappeared completely. The patient died 52 days after operation, but no thromboembolic episode was observed during the course, and no fresh thrombus was found within the left ventricle at autopsy. The bisected diastolic driving method served as an aid to prevent stagnation of blood and thrombus formation within the native left ventricle in this patient with a left ventricular assist device. Keywords:
left ventricular thrombus, pneumatic pulsatile pump, systemic thromboembolism
Systemic thromboembolism is a serious complication in patients with left ventricular assist devices’. The antithrombogenicity of the device has been frequently reported, and refinements in antithrombogenic materials have been investi ated at many institutions. Recently, Nakatani et al. 5 reported that the unloaded failing heart is another source of thrombus formation and recommended local heparinization within the left ventricle to prevent this complication. This report describes a patient with a left ventricular assist device who showed transient resolution of a smoke-like swirling image (echo) within the left ventricle during simultaneous use of an intra-aortic balloon assist.
Case report A 20-year-old woman suffering from severe mitral regurgitation combined with annuloaortic ectasia due to Marfan’s syndrome, underwent mitral valve replacement and a modified Bentall’s procedure. The patient was weaned slowly from cardiopulmonary bypass, and the heart displayed evidence of profound myocardial
Correspondence
84
to: Dr T. Sakamoto
failure with a mean(range) arterial pressure of 60(56-72) mmHg during administration of 15 @kg per min of dobutamine, 20pg/min of norepinephrine and intra-aortic balloon support. After cardiopulmonary bypass was resumed, a pneumatically driven ventricular assist device was interposed between the left atrium and the ascending aorta. The patient was then gradually weaned from cardiopulmonary bypass. The devices (left ventricular assist device and intra-aortic balloon) took over complete support of the circulation, and haemodynamic parameters included a mean(range) aortic pressure of 77(65-101) mmHg, pulmonary arterial pressure of 18 (12-30) mmHg, pulmonary capillary wedge pressure of 12mmHg, cardiac output determined by thermodilution of 4.1 l/min and left ventricular assist device-generated blood flow of 3.7Vmin. At that time, the intra-aortic balloon operated at a one-to-eight assist rate. After 1 week of support, the heart showed no improvement, and haemodynamic data obtained 1 min after the cessation of circulatory support were as follows: mean(range) aortic pressure 53(39-76) mmHg, pulmonary capillary wedge pressure 33 mmHg and cardiac output 2.38 l/min. However, during the assist, cardiac output was 4.4l/min, mean(range) aortic pressure 86(65-l 12) mmHg, pulmonary capillary wedge pressure 18 mmHg and pump flow 3.71Imin; no other organ dysfunction had been observed. Transoesophageal echocardiography was performed with a CARDIOVASCULAR SURGERY FEBRUARY 1995 VOL 3 NO 1
S-MHz transducer attached to the tip of a commercially available gastroscope (Hewlett-Packard 77025A, SONOS 500; Hewlet-Packard, Andover, Massachusetts, USA) on the 12th postoperative day. Within the left ventricle there was a prominent smoke-like swirling image with the left ventricular assist device only (Figure I). The image disappeared immediately after the combined use of intra-aortic balloon and left ventricular assist device (Figure 2). A bisected diastolic driving method (Figure 3) that the authors3 devised to regulate the simultaneous use of a left ventricular assist device and intra-aortic balloon assist without competition was used. To perform this bisected method, the aortic diastolic interval was measured from the central aortic Figure 3 Schema explaining bisected diastolic driving. The dotted line shows a natural central aortic pressure wave originating from the patients own heart. and the solid line a counterpulsed central aorbc pressure wave produced by the bisected diastolic driving mode. The wave in this mode forms three curves: the first is generated by the natural heart, the second by the left ventricular assist device and the third by the intra-aortic balloon pump. LVAD. left ventricular assist device: IABP. intra-aortic balloon pump: D. diastole
Figure 1 Transoesophageal echocardiogram showing a prominent smoke-like swirling echo (arrows) within the natural left ventricle during left ventricular assist device assist
pressure trace obtained through the tip of the intraaortic balloon catheter. The left ventricular assist device was driven during the first half of diastole, while the intra-aortic balloon assist was apphed during the latter half (Figure 3). During bisected diastolic driving assist, there was a 0.7-0.8-l/min increase in cardiac output and a 3-mmHg decrease in pulmonary capillary wedge pressure compared with values when using left ventricular assist device assist only. The swirling echo within the left ventricle appeared only during discontinuation of intra-aortic balloon pump assist. The authors continued to use bisected diastolic driving to prevent thrombus formation within the native left ventricle, The patient died on day 52 after aperation as a result of multiorgan failure with cytomegalovirus lung infection while still receiving circulatory assist. At postmortem examination, neither fresh mural thrombus within the left ventricle, which showed old and severe subendocardial myocardial infarction, nor infarction of the major organs was observed.
Discussion
Flgure 2 Transoesophageal echocardiogram without smoke-like echo during combined use of left ventricular assist device and intra-aortic balloon pump on bisected diastolic driving mode in the same patient
CAFtDlOVASCULAR SURGERY FEBRUARY 1995 VOL 3 NO 1
Many reports have focused on the prevention of thrombus formation within the artificial blood pump. Some authors recommend the use of anticoagulation during circulatory support with ventricular assist devices. However, the demonstration of left ventricular thrombus influences important clinical decisions regarding anticoagulation. Two-dimensional echocardiography has demonstrated that left ventricular thrombi are common in patients with acute anterior myocardial infarction4, and transoesophageal e&cardiography also recently displayed left ventricular thrombi in
85
Cardiaccasereport postcardiotomy cases with assist devicess. Nakatani et al2 recommended local anticoagulation, in which the depressed left ventricle is heparinized through the selectively inserted catheter, to reduce and prevent left ventricular thrombus formation. The authors have devised and applied the synchronized combined use of left ventricular assist device and intra-aortic balloon for patients with renal dysfunction and regular rhythms, and obtained significant clinical improvement3. The present case showed profoundly impaired left ventricle contraction that resulted in dependence on the left ventricular assist device. After 3 or 4 days of assist, the left ventricular assist device is usually discontinued daily for periods up to 2min in order to permit a sequential evaluation of the patient’s cardiac function. In this case, severe left ventricular dysfunction continued, and a transoesophageal examination was performed for anatomical evaluation. Prominent smoke-like swirling echoes were observed within the left ventricle during left ventricular assist device assist, but the echo disappeared immediately after the start of bisected diastolic driving. This phenomenon occurred repeatedly and suggested that the unloading effect of the intra-aortic balloon increased cardiac output by the failing left ventricle up to 1.4-1.5 l/min and the increased flow via the ventricle was sufficient to dissipate the smoke-like swirling echo, which has been clinically observed at various sites with stagnant blood flow and is thought to represent the beginning of thrombus formation2. Many investigators have studied the pathogenesis of left ventricular thrombus and the effect of various antithrombotic regimens in acute anterior myocardial infarction6-8. However, the effects of intra-aortic balloon support on left ventricle thrombus formation have not been previously studied. The authors suggest that, in patients with postcardiotomy cardiogenic shock, combined use of intraaortic balloon and left ventricular assist device as bisected diastolic driving is a useful way to reduce or
86
prevent thrombus ventricle.
formation
within
the depressed left
Acknowledgement The authors thank Marc T. Swartz of the Department of Surgery, St Louis University, for helpful comments and review of the manuscript.
References 1. Pennington
2. 3.
4.
5.
7. 6.
8.
DG, McBride LR, Swartz MT et al. Use of the Pierce-Donachy ventricular assist device in patients with cardiogenic shock after cardiac operations. Ann Tboruc Surg 1989; 47: 130-5. Nakatani T, Noda H, Beppu S et al. Thrombus in a natural left ventricle during left ventricular assist: another thromboembolic risk factor. ASAIO Tram 1990; 36: M711-14. Sakamoto T, Suzuki A, Atsumi K. Bisected diastolic driving to control combined clinical use of left ventricular assist device and intra-aortic balloon pumping and its effect on renal function. ASAIO Tram 1987; 33: 708-13. Delemarre BJ, Visser CA, Bot H, Dunning AJ. Prediction of apical thrombus formation in acute myocardial infarction based on left ventricular spatial flow pattern. / Am CON Curdiol 1990; 15: 355-60. Brack M, Olson JO, Pedersen WR et al. Transesophageal echocardiography in patients with mechanical circulatory assistance. Ann Tboruc Suyg 1991; 52: 1306-9. Turpie AGG. Prevention of left ventricular mural thrombus. Am J Curdiol 1989; 64: B41-3. Kupper, AJF, Verheugt FWA, Peels CH et ul. Left ventricular thrombus incidence and behavior studied by serial twodimensional echocardiography in acute anterior myocardial infarction: left ventricular wall motion, systemic embolism and oral anticoagulation. / Am Co11Curdiol 1989; 13: 1514-20. Bhatnagar SK, Al-Yusuf AR. Effects of intravenous recombinant tissue type plasminogen activator therapy on the incidence and associations of left ventricular thrombus in patients with a first acute Q wave anterior myocardial infarction. Am Heart J 1991; 122: 1251-6.
Paper accepted 11 March 1994
CARDIOVASCULAR SURGERY FEBRUARY 199s VOL 3 NO 1
Cardiovascular
Prevention of left ventricular thrombus formation during pneumatic pump assist T. Sakamoto,T. Maruyama,T. Sugano,H. AraiandA. Suzuki Department of Cardiothoracic Surgery, School of Medicine, Tokyo Medical and Dental University, f-5-45, Yishima, Bun&vo-ku, Tokyo, I 1.3 Japan A postcardiotomy patient with a pneumatic pulsatile pump for left ventricular assist showed a smoke-like swirling echo within the left ventricle during pump assist. The image disappeared partially during intra-aortic balloon pumping, which was performed as usual. Subsequently, three pumps (native left ventricle, pneumatic and intra-aortic balloon) were driven synchronously: that is, the ventricular assist pump ejected the blood in the first half of the diastole of the native heart beat, and the intra-aortic balloon was inflated during the second half. With this bisected diastolic driving, the abnormal echo disappeared completely. The patient died 52 days after operation, but no thromboembolic episode was observed during the course, and no fresh thrombus was found within the left ventricle at autopsy. The bisected diastolic driving method served as an aid to prevent stagnation of blood and thrombus formation within the native left ventricle in this patient with a left ventricular assist device. Keywords:
left ventricular thrombus, pneumatic pulsatile pump, systemic thromboembolism
Systemic thromboembolism is a serious complication in patients with left ventricular assist devices’. The antithrombogenicity of the device has been frequently reported, and refinements in antithrombogenic materials have been investi ated at many institutions. Recently, Nakatani et al. 5 reported that the unloaded failing heart is another source of thrombus formation and recommended local heparinization within the left ventricle to prevent this complication. This report describes a patient with a left ventricular assist device who showed transient resolution of a smoke-like swirling image (echo) within the left ventricle during simultaneous use of an intra-aortic balloon assist.
Case report A 20-year-old woman suffering from severe mitral regurgitation combined with annuloaortic ectasia due to Marfan’s syndrome, underwent mitral valve replacement and a modified Bentall’s procedure. The patient was weaned slowly from cardiopulmonary bypass, and the heart displayed evidence of profound myocardial
Correspondence
84
to: Dr T. Sakamoto
failure with a mean(range) arterial pressure of 60(56-72) mmHg during administration of 15 @kg per min of dobutamine, 20pg/min of norepinephrine and intra-aortic balloon support. After cardiopulmonary bypass was resumed, a pneumatically driven ventricular assist device was interposed between the left atrium and the ascending aorta. The patient was then gradually weaned from cardiopulmonary bypass. The devices (left ventricular assist device and intra-aortic balloon) took over complete support of the circulation, and haemodynamic parameters included a mean(range) aortic pressure of 77(65-101) mmHg, pulmonary arterial pressure of 18 (12-30) mmHg, pulmonary capillary wedge pressure of 12mmHg, cardiac output determined by thermodilution of 4.1 l/min and left ventricular assist device-generated blood flow of 3.7Vmin. At that time, the intra-aortic balloon operated at a one-to-eight assist rate. After 1 week of support, the heart showed no improvement, and haemodynamic data obtained 1 min after the cessation of circulatory support were as follows: mean(range) aortic pressure 53(39-76) mmHg, pulmonary capillary wedge pressure 33 mmHg and cardiac output 2.38 l/min. However, during the assist, cardiac output was 4.4l/min, mean(range) aortic pressure 86(65-l 12) mmHg, pulmonary capillary wedge pressure 18 mmHg and pump flow 3.71Imin; no other organ dysfunction had been observed. Transoesophageal echocardiography was performed with a CARDIOVASCULAR SURGERY FEBRUARY 1995 VOL 3 NO 1
S-MHz transducer attached to the tip of a commercially available gastroscope (Hewlett-Packard 77025A, SONOS 500; Hewlet-Packard, Andover, Massachusetts, USA) on the 12th postoperative day. Within the left ventricle there was a prominent smoke-like swirling image with the left ventricular assist device only (Figure I). The image disappeared immediately after the combined use of intra-aortic balloon and left ventricular assist device (Figure 2). A bisected diastolic driving method (Figure 3) that the authors3 devised to regulate the simultaneous use of a left ventricular assist device and intra-aortic balloon assist without competition was used. To perform this bisected method, the aortic diastolic interval was measured from the central aortic Figure 3 Schema explaining bisected diastolic driving. The dotted line shows a natural central aortic pressure wave originating from the patients own heart. and the solid line a counterpulsed central aorbc pressure wave produced by the bisected diastolic driving mode. The wave in this mode forms three curves: the first is generated by the natural heart, the second by the left ventricular assist device and the third by the intra-aortic balloon pump. LVAD. left ventricular assist device: IABP. intra-aortic balloon pump: D. diastole
Figure 1 Transoesophageal echocardiogram showing a prominent smoke-like swirling echo (arrows) within the natural left ventricle during left ventricular assist device assist
pressure trace obtained through the tip of the intraaortic balloon catheter. The left ventricular assist device was driven during the first half of diastole, while the intra-aortic balloon assist was apphed during the latter half (Figure 3). During bisected diastolic driving assist, there was a 0.7-0.8-l/min increase in cardiac output and a 3-mmHg decrease in pulmonary capillary wedge pressure compared with values when using left ventricular assist device assist only. The swirling echo within the left ventricle appeared only during discontinuation of intra-aortic balloon pump assist. The authors continued to use bisected diastolic driving to prevent thrombus formation within the native left ventricle, The patient died on day 52 after aperation as a result of multiorgan failure with cytomegalovirus lung infection while still receiving circulatory assist. At postmortem examination, neither fresh mural thrombus within the left ventricle, which showed old and severe subendocardial myocardial infarction, nor infarction of the major organs was observed.
Discussion
Flgure 2 Transoesophageal echocardiogram without smoke-like echo during combined use of left ventricular assist device and intra-aortic balloon pump on bisected diastolic driving mode in the same patient
CAFtDlOVASCULAR SURGERY FEBRUARY 1995 VOL 3 NO 1
Many reports have focused on the prevention of thrombus formation within the artificial blood pump. Some authors recommend the use of anticoagulation during circulatory support with ventricular assist devices. However, the demonstration of left ventricular thrombus influences important clinical decisions regarding anticoagulation. Two-dimensional echocardiography has demonstrated that left ventricular thrombi are common in patients with acute anterior myocardial infarction4, and transoesophageal e&cardiography also recently displayed left ventricular thrombi in
85
Cardiaccasereport postcardiotomy cases with assist devicess. Nakatani et al2 recommended local anticoagulation, in which the depressed left ventricle is heparinized through the selectively inserted catheter, to reduce and prevent left ventricular thrombus formation. The authors have devised and applied the synchronized combined use of left ventricular assist device and intra-aortic balloon for patients with renal dysfunction and regular rhythms, and obtained significant clinical improvement3. The present case showed profoundly impaired left ventricle contraction that resulted in dependence on the left ventricular assist device. After 3 or 4 days of assist, the left ventricular assist device is usually discontinued daily for periods up to 2min in order to permit a sequential evaluation of the patient’s cardiac function. In this case, severe left ventricular dysfunction continued, and a transoesophageal examination was performed for anatomical evaluation. Prominent smoke-like swirling echoes were observed within the left ventricle during left ventricular assist device assist, but the echo disappeared immediately after the start of bisected diastolic driving. This phenomenon occurred repeatedly and suggested that the unloading effect of the intra-aortic balloon increased cardiac output by the failing left ventricle up to 1.4-1.5 l/min and the increased flow via the ventricle was sufficient to dissipate the smoke-like swirling echo, which has been clinically observed at various sites with stagnant blood flow and is thought to represent the beginning of thrombus formation2. Many investigators have studied the pathogenesis of left ventricular thrombus and the effect of various antithrombotic regimens in acute anterior myocardial infarction6-8. However, the effects of intra-aortic balloon support on left ventricle thrombus formation have not been previously studied. The authors suggest that, in patients with postcardiotomy cardiogenic shock, combined use of intraaortic balloon and left ventricular assist device as bisected diastolic driving is a useful way to reduce or
86
prevent thrombus ventricle.
formation
within
the depressed left
Acknowledgement The authors thank Marc T. Swartz of the Department of Surgery, St Louis University, for helpful comments and review of the manuscript.
References 1. Pennington
2. 3.
4.
5.
7. 6.
8.
DG, McBride LR, Swartz MT et al. Use of the Pierce-Donachy ventricular assist device in patients with cardiogenic shock after cardiac operations. Ann Tboruc Surg 1989; 47: 130-5. Nakatani T, Noda H, Beppu S et al. Thrombus in a natural left ventricle during left ventricular assist: another thromboembolic risk factor. ASAIO Tram 1990; 36: M711-14. Sakamoto T, Suzuki A, Atsumi K. Bisected diastolic driving to control combined clinical use of left ventricular assist device and intra-aortic balloon pumping and its effect on renal function. ASAIO Tram 1987; 33: 708-13. Delemarre BJ, Visser CA, Bot H, Dunning AJ. Prediction of apical thrombus formation in acute myocardial infarction based on left ventricular spatial flow pattern. / Am CON Curdiol 1990; 15: 355-60. Brack M, Olson JO, Pedersen WR et al. Transesophageal echocardiography in patients with mechanical circulatory assistance. Ann Tboruc Suyg 1991; 52: 1306-9. Turpie AGG. Prevention of left ventricular mural thrombus. Am J Curdiol 1989; 64: B41-3. Kupper, AJF, Verheugt FWA, Peels CH et ul. Left ventricular thrombus incidence and behavior studied by serial twodimensional echocardiography in acute anterior myocardial infarction: left ventricular wall motion, systemic embolism and oral anticoagulation. / Am Co11Curdiol 1989; 13: 1514-20. Bhatnagar SK, Al-Yusuf AR. Effects of intravenous recombinant tissue type plasminogen activator therapy on the incidence and associations of left ventricular thrombus in patients with a first acute Q wave anterior myocardial infarction. Am Heart J 1991; 122: 1251-6.
Paper accepted 11 March 1994
CARDIOVASCULAR SURGERY FEBRUARY 199s VOL 3 NO 1