Mitral Valvuloplasty by Inoue Balloon Under Transthoracic Echocardiographic Guidance

Mitral Valvuloplasty by Inoue Balloon Under Transthoracic Echocardiographic Guidance Vijay Trehan, DM, Saibal Mukhopadhyay, DM, Arima Nigam, MD, Jamal Yusuf, DM, Vimal Mehta, DM, Mohit Dayal Gupta, MD, MP, Meenahalli Palleda Girish, and Sanjay Tyagi, DM, New Delhi, India

Background: Mitral valvuloplasty traditionally performed under fluoroscopic guidance has emerged as an effective nonsurgical technique for the treatment of symptomatic patients with mitral stenosis. We undertook a study to evaluate the feasibility of performing valvuloplasty by the Inoue balloon solely under transthoracic echocardiographic (TTE) guidance with the backup of transesophaeal echocardiography (TEE) and fluoroscopy. Methods: Between September 2003 and July 2004, mitral valvuloplasty using the Inoue balloon was performed solely under TTE guidance in the catheterization laboratory with backup of fluoroscopy and TEE in 75 patients (52 female patients, including 18 who were pregnant, and 23 male patients) with symptomatic mitral stenosis (New York Heart Association class II-IV) with satisfactory TTE window and valve morphology suitable for valvuloplasty. Results: The procedure was technically successful (no requirement of TEE or fluoroscopy) in 68 patients (89%). TEE was required for septal puncture in 3 patients whereas fluoroscopic assistance was required to complete the procedure in 4 patients. Procedural

Balloon mitral valvuloplasty (BMV) has emerged as

an effective nonsurgical technique for the treatment of patients with symptomatic mitral stenosis. Traditionally the procedure has been done under fluoroscopic guidance. To achieve better visualization of intracardiac anatomy and to reduce radiation hazards, transesophageal echocardiography (TEE)1-6 has been used to guide the procedure but no report is yet available in the literature of BMV being performed solely under transthoracic echocardiographic (TTE) guidance. This study was undertaken to evaluate the feasibility of performing BMV solely under TTE guidance without using fluoroscopy. From the Department of Cardiology, G B Pant Hospital. Reprint requests: Saibal Mukhopadhyay, Room No. 126, Academic Block, First Floor, Department of Cardiology, G B Pant Hospital, New Delhi, India (E-mail: saibalmukhopadhyay@ yahoo.com). 0894-7317/$30.00 Copyright 2005 by the American Society of Echocardiography. doi:10.1016/j.echo.2005.01.024

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success after valvuloplasty (doubling of mitral valve area or mean gradient across mitral valve < 5 mm Hg in absence of complications like severe mitral regurgitation or tamponade) was achieved in 70 patients. There was an increase in mean mitral valve area as assessed echocardiographically from 0.84 ⴞ 0.16 cm2 to 1.7 ⴞ 0.27 cm2 with decrease in mean diastolic gradient from 27.2 ⴞ 8.4 mm Hg (18-36 mm Hg) to 5.2 ⴞ 4.1 mm Hg (3-14 mm Hg). The mean procedure time was 27.2 ⴞ 8.4 minutes (15-45 minutes). Mild mitral regurgitation appeared or increased in severity to moderate degree as assessed by color Doppler during the procedure in 11 patients (14.6%) but no patient developed severe mitral regurgitation. No patient had cardiac tamponade as puncture of the septum under TTE guidance prevents inadvertent puncture of the aorta, coronary sinus, inferior vena cava, and right atrial and left atrial wall that sometimes occurs during septal puncture under fluoroscopic guidance. Conclusion: Balloon mitral valvuloplasty under sole TTE guidance is safe and feasible in experienced hands. (J Am Soc Echocardiogr 2005;18:964-969.)

METHODS Study Group Between September 2003 and July 2004, BMV was performed solely under TTE guidance on 75 symptomatic patients with severe mitral stenosis (52 female and 23 male) of 114 patients screened, with age ranging from 10 to 68 years (mean age: 30 ⫾ 12). There were 18 patients (24%) in atrial fibrillation; 15 (20%) were in New York Heart Association class IV, 30 (40%) in class III, and the rest (40%) were in class II. In all, 18 patients had restenotic valves (15 having undergone BMV earlier and 3 with closed mitral commissurotomy [CMV]) (Table 1). Echocardiographic Evaluation All patients underwent a detailed TTE evaluation (HewlettPackard Sonos 5500) with 2.5-MHz transducer to assess if the echocardiographic window was adequate to carry out the procedure under echocardiographic guidance and also if their valve apparatus was suitable for valvuloplasty. The morphology of the mitral valve and severity of mitral stenosis

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Table 1 Clinical characteristics of patients who underwent balloon mitval valvuloplasty Parameter

Age, yrs Mean ⫾ SD (range) Male: female Pregnant n (%) NHYA class n (%) Class II Class III Class IV Atrial fibrillation n (%) Previous BMV/CMV n (%) Echocardiographic score Mean ⫾ SD

Value

30 ⫾ 12 (10–68) 23:52 (n ⫽ 75) 18 (24) 30 (40%) 30 (40) 15 (20) 24 (32) 18 (24) 6.6 ⫾ 2.4

BMV, Balloon mitral valvuloplasty; CMV, closed mitral commissurotomy; NYHA, New York Heart Association.

was fully assessed by 2-dimensional echocardiography and Doppler studies. Mean gradient across the mitral valve was recorded. Mitral valve area was assessed by both pressure half-time method and by planimetry. All patients undergoing the procedure had critical mitral stenosis (mitral valve area ⱕ 1 cm2). Mitral valve score was determined using Wilkins scoring system. Pulmonary artery systolic pressure was estimated using tricuspid regurgitation Doppler signal velocity. For patients in whom left atrial (LA) appendage appeared hazy or was not well visualized, TEE was done preprocedure to exclude the presence of LA appendage clot. In all, 28 patients were excluded because of presence of LA/LA appendage thrombus, severe mitral regurgitation (MR), or bilateral commissural calcification, whereas 11 (9.6%) patients were excluded because of very poor TTE window even after use of harmonic imaging. No patient was denied because of a high Wilkins score.

Figure 1 Arrow showing J-tipped 0.032-in wire in inferior vena cava.

Procedure Informed written consent was taken from all the patients before undertaking the procedure. The TTE system used was Hewlett-Packard Sonos 5500 (Hewlett-Packard, Palo Alto, Calif) with 2.5-MHz transducer. Right groin was used for vascular access (4F sheath for arterial access and 7F sheath for venous access). A 0.032-in guidewire was introduced through the venous sheath and advanced into the right atrium (RA) under TTE guidance in subcostal sagittal view showing inferior vena cava and RA junction (Figure 1). A 7F Mullin’s dilator (St Jude’s Medical, Minnetonka, Minn) was advanced over this to RA in the same view. The 0.032-in guidewire was exchanged with a Brockenbrough needle that was advanced within the Mullin’s dilator (St Jude’s, Medical) just short of its tip (Figure 2). The assembly of the Brockenbrough needle and the Mullin’s dilator (St Jude’s Medical) was then manipulated in the RA in subcostal or apical 4-chamber view with the index of the Brockenbrough needle pointing posteromedially (4 o’clock or 5 o’clock position) at the groin (similar to the manipulation done under fluoroscopic guidance) until the tip of the Mullins dilator tented midseptum in the region of fossa ovalis (Figure

Figure 2 Arrow showing septal puncture needle within Mullins dilator at inferior vena cava and right atrial junction. 3). At this juncture, the interatrial septum (IAS) was punctured usually by firm pressure on the Mullin’s sheath and correct entry of the needle into the LA was confirmed by injection of agitated saline through the Brockenbrough needle and visualizing it as contrast in the LA (Figure 4) and by observing the LA pressure waveform. After this, mean LA pressure was recorded. After removing the needle from the Mullin’s dilator (St Jude’s Medical), the floppy-tipped 0.025-in spring wire of the Inoue system (Toray Industries Inc, Tokyo, Japan) was introduced through the Mullin’s dilator into the LA. The loops of the round wire could be easily visualized in the LA on TTE (Figure 5). The IAS was then dilated with the 14F dilator passed over this wire (as seen in 4-chamber view). Then an Inoue balloon catheter (Toray Industries Inc) of appropriate size ([height of the patient in cm/10] ⫹10) was advanced over the round wire into the LA under TTE guidance. After withdrawal of the round wire the distal part

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Figure 3 Arrow showing tenting of fossa ovalis by assembly of septal puncture needle within Mullin’s dilator.

Figure 4 Saline contrast in left atrium (LA) confirming entry of septal puncture needle in LA. of the Inoue balloon was partially inflated with normal saline (Figure 6) with the following objectives: (1) to increase the visibility of the balloon on TTE; (2) to prevent inadvertent prolapse of the balloon into the RA during manipulation; and (3) to facilitate its flow-directed passage towards the mitral valve. The balloon catheter was then manipulated with the help of J-shaped stylet, to direct it toward the mitral valve and guide it through the mitral valve orifice into the left ventricle (LV) in apical 4-chamber view or parasternal long-axis view (Figure 7). In 8 patients, where entry by the straight balloon technique failed to align the balloon with the mitral valve, entry by formation of reverse loop was also successful (Figure 8). As the partially inflated balloon started to bob at the mitral valve orifice, the distal part of the balloon was deflated and pushed into the LV. After confirming on TTE that the balloon was lying freely in the LV without being

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Figure 5 Arrowheads showing loops of round wire in left atrium in 4-chamber view.

Figure 6 Arrow showing partially inflated balloon in left atrium. straddled in the chordae, initially the distal part of the balloon and then the proximal part was inflated across the mitral valve (Figure 9). We followed the principal of graded balloon dilatation, starting with 4 mm less then the maximum diameter of the balloon appropriate for the patient and incrementally increasing it by 1 mm. After each dilatation, the mitral valve area was determined by planimetry and degree of MR by color Doppler. Extent of commissural split was also assessed after each dilatation. Procedural success was defined by the doubling of the mitral valve area as measured by planimetry or decrease in pressure gradient across mitral valve to less than 5 mm Hg measured hemodynamically in the absence of complications like severe MR or acute tamponade. Technical success was defined as completing the procedure under sole TTE guidance without help of fluoroscopy or TEE.

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Figure 7 A, Path traversed by balloon from right atrium (RA) to left atrium (LA) across septum into left ventricle by straight balloon technique. B, Schematic diagram.

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Figure 8 A, Path traversed by balloon from right atrium (RA) to left atrium (LA) across septum into left ventricle by reverse loop technique. B, Schematic diagram.

Statistical Analysis All data are expressed as mean ⫾ SD. Comparison of data before and after BMV was performed using the paired t test. A P value ⬍ .05 was considered significant.

RESULTS Our entire study group comprised of 75 patients. The cause of mitral stenosis was rheumatic heart disease in all patients. BMV was technically successful (no use of TEE or fluoroscopy to guide the procedure) in 68 cases (89%). In 3 patients TEE was required to guide the septal puncture and in 4 patients fluoroscopic assistance had to be taken to complete the procedure. Procedural success was achieved in 70 patients (93.3%). All the unsuccessful cases were patients who had undergone either BMV or CMV previously and had extensive subvalvular fusion. Overall, mitral valve area increased significantly after BMV from 0.84 ⫾ 0.16 to 1.7 ⫾ 0.27 cm2 (P ⬍

Figure 9 Balloon being inflated across mitral valve with arrowheads showing constriction of balloon by fused commissures.

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Table 2 Hemodynamic parameters before and after the procedure Sno:

Parameter

Pre-BMV mean ⴞ SD (range)

Post-BMV mean ⴞ SD (range)

1 2 3

MVA cm2 Mean LA pressure, mm Hg Mean diastolic pressure gradient, mm Hg

0.84 ⫾ 0.16 36.4 ⫾ 5.6 27.2 ⫾ 8.4 (18–36)

1.7 ⫾ 0.27 11.5 ⫾ 2.9 5.2 ⫾ 4.1 (3–14)

BMV, Balloon mitral valvuloplasty; LA, left atrial; MVA, mitral valve area; Sno, serial number.

.001) and there was significant decrease in mean transmitral pressure gradient from 27.2 ⫾ 8.4 to 5.2 ⫾ 4.1 mm Hg (P ⬍ .001). The mean LA pressure also decreased significantly after valvuloplasty from 36.4 ⫾ 5.6 to 11.5 ⫾ 2.9 mm Hg (P ⬍ .001) (Table 2). Moderate MR was present in 8 patients and none of these patients had increase in the severity of MR postprocedure. In all, 11 patients (14.6%) developed mild MR after the procedure. However, no patient developed severe MR after the procedure. Mean procedural time was 27.2 ⫾ 8.4 minutes (15-45 minutes). Duration of the procedure was slightly longer in the initial few cases. It may have been a result of our learning curve, as in the later cases the procedure time decreased considerably. None of the patients had cardiac tamponade, systemic thromboembolism or any groin complication. None of the pregnant patients had fetal abortion after the procedure or at 1-month follow-up.

DISCUSSION Traditionally BMV has been performed under fluoroscopic guidance. Some investigators have used TEE alone or as an adjunct to fluoroscopy. This is the first study undertaken by us to assess the feasibility and efficacy of performing BMV under sole TTE guidance with backup of fluoroscopy and TEE. TTE can guide every step of BMV adequately. Septal puncture can be very well guided by TTE. Before puncturing the septum, visualization of adequate tenting of the septum is essential because of the fact that when the assembly of Mullin’s dilator (St Judes Medical) and Brockenbrough needle is manipulated in the RA, there is acoustic shadowing visible in LA giving the deceptive appearance of assembly being in LA (Figure 10). Therefore, we considered tenting of the midseptum (region of fossa ovalis) by the Mullin’s dilator (St Judes Medical) to be an essential prerequisite before puncturing the septum. Further, we have found that the septal anatomy is best visualized in those patients in whom significant tricuspid regurgitation and/or pulmonary hypertension is present, which leads to large RA. If the LA is hugely dilated and the RA is very small, TTE-guided septal puncture may be difficult and should be avoided, as we encountered in one of our cases. Fluoroscopic assistance had to be taken in 4 patients. The first case was a patient with critical

Figure 10 Arrowheads showing acoustic shadowing giving false appearance of needle in left atrium.

mitral stenosis having a huge LA with septum bulging into the RA to such an extent that the RA was very difficult to visualize. IAS in 4-chamber view appeared very close to RA free wall and tenting of the septum was not adequately visualized in any TTE view. Therefore, fluoroscopic assistance was taken for IAS puncture. The rest of the procedure was then successfully completed under TTE guidance. The second case, where fluoroscopic assistance had to be taken was a pregnant woman (in second trimester) of critical MS. She was one of our early patients who went into acute pulmonary edema during the procedure and recourse to fluoroscopy was taken to cut short the procedure time. The third case, where fluoroscopic assistance was taken was to visualize inadvertent rotation of the Mullin’s dilator (St Judes Medical) in the LA. In this case, immediately after the IAS puncture and removal of the Brockenbrough needle, the Mullin’s dilator (St Judes Medical) somehow rotated and went into the right upper pulmonary vein. On TTE, it appeared as if it had gone back to the RA but fluoroscopy revealed the real situation. Subsequently in another patient when a similar situation was encountered, we immediately injected a large amount of agitated saline, which revealed that the contrast was coming from the right upper pulmonary vein to the LA. Hence, during the procedure, if

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any part of the assembly appears to be in an abnormal position, contrast echocardiography can help in assessing its exact location. The last case where fluoroscopic assistance had to be taken was one in which the IAS was punctured successfully but the balloon could not be negotiated over the round wire. Fluoroscopy revealed that although the path of the round wire was correct, there was an acute kink in the round wire. After exchange of this round wire with another one, the balloon could be easily negotiated over it and the rest of the procedure was successfully completed under TTE guidance. In 3 of our cases help of TEE was taken to visualize tenting of the fossa ovalis, which was not adequately visualized on TTE.

(very high or very low) not appreciated on fluoroscopy that, in turn, leads to difficulty in aligning the balloon for entry into the LV. Emergency BMV. TTE-guided BMV can be attempted for patients who are critically ill presenting at odd hours when organization of the catheterization laboratory team may be very difficult.

Advatages of TTE-guided BMV

Although traditionally BMV has been performed under fluoroscopic guidance, it is feasible and safe to perform the procedure under sole TTE guidance by experienced operators.

Avoidance of radiation hazard to the fetus in pregnant patients. It is of great advantage in se-

verely symptomatic pregnant patients with mitral stenosis requiring mechanical relief of their obstruction before 20 weeks of gestation, when mitral valvuloplasty under fluoroscopic assistance is absolutely contraindicated7,8 because of risk of fetal teratogenicity to radiation. Avoidance of cardiac tamponade secondary to stitch phenomenon. In patients with mitral stenosis in

whom the septal anatomy is usually distorted, septal puncture under fluoroscopic guidance by experienced operators using standard anatomic landmarks may occasionally lead to inadvertent puncture of the aorta, coronary sinus, inferior vena cava, or RA and LA wall transpericardially without actually puncturing the septum (stitch phenomenon). Although puncture of aorta, coronary sinus, or inferior vena cava can readily be detected by following the principle of recording pressure, doing oximetry, or injecting contrast after needle puncture (needle can be promptly withdrawn without any sequelae), such precautions fail to detect LA entry transpericardially through the RA wall without actually puncturing the septum. The wrong puncture site becomes evident only after dilatation of the septal puncture site by the 14F dilator and its withdrawal leading to development of cardiac tamponade secondary to tear in RA and LA wall. Having the largest single center experience of performing BMV,9 there were 4 cases of cardiac tamponade in the last year while performing BMV in aproximately 700 patients–all secondary to stitch phenomenon.10,11 This phenomenon can be avoided, if septal puncture is done under echocardiographic guidance. Avoidance of inappropriate sites of puncture of IAS. Optimal site of puncture is midseptum in the

region of fossa ovalis. However, distortion of the septal anatomy in patients of mitral stenosis can lead to puncture of the septum at inappropriate sites

Limitations of TTE-guided BMV Although feasible, TTE-guided BMV cannot be performed in all patients, as it requires a good transthoracic window. This may lead to exclusion of patients with chronic obstructive airway disease, those having thick chest wall or any deformity of the chest. Conclusion

REFERENCES 1. Ballal RS, Mahan EF III, Nanda NC, Dean LS. Utility of transesophageal echocardiography in interatrial septal puncture during percutaneous mitral balloon commissurotomy. Am J Cardiol 1990;66:230-2. 2. Park SH, Kim MA, Hyon MS. The advantages of on-line transesophageal echocardiography guide during percutaneous balloon mitral valvuloplasty. J Am Soc Echocardiogr 2000;13:26-34. 3. Vilacosta I, Iturralde E, Roman JAS, Gomez-Recio M, Romero C, Jimenez J, et al. Transesophageal echocardiographic monitoring of percutaneous mitral balloon valvulotomy. Am J Cardiol 1992;70:1040-4. 4. Chiang C, Hsu L, Chu P, Ho W, Lo H, Chang C. Feasibility of simplifying balloon mitral valvuloplasty by obviating left sided cardiac catheterization using on line guidance with transesophageal echocardiography. Chest 2003;123:1957-63. 5. Jaarsma W, Visser CA, Suttorp MJ, Haagen FD, Ernst SM. Transesophageal echocardiography during percutaneous balloon mitral valvuloplasty. J Am Soc Echocardigr 1990;3:384-91. 6. Chan K, Marquis J, Ascah C, Morton B, Baird M. Role of transesophageal echocardiography in percutaneous balloon mitral valvuloplasty. Echocardiography 1990;7:115-23. 7. Brent RL. The effect of embryonic and fetal exposure to x-ray microwaves and ultrasound: counselling the pregnant and nonpregnant patient about these risks. Semin Oncol 1989;16:347-68. 8. Gray JE. The radiation hazard: let’s put it in perspective. Mayo Clin Proc 1979;54:809-13. 9. Arora R, Kalra GS, Singh S, Mukhopadhyay S, Kumar A, Mohan JC, et al. Percutaneous transvenous mitral commissurotomy: immediate and long-term follow-up results. Catheter Cardiovasc Interv 2002;55:450-6. 10. Trehan V, Mukhopadhyay S, Yaduvanshi A, Mehta V, Sunil Roy TN, Nigam A, et al. Novel non-surgical method of managing cardiac perforation during percutaneous transvenous mitral commissurotomy. Indian Heart J 2004;56:328-32. 11. Trehan V, Yusuf J, Mukhopadhyay S, Gupta MD, Mehta V, Girish MP, et al. Percutaneous management of cardiac perforation during mitral commissurotomy by a new technique. Indian Heart J 2004;56:452.