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Percutaneous intracoronary Raman spectroscopy
Abstracts / Cardiovascular Revascularization Medicine 8 (2007) 116 – 154 be the treatment of choice for patients with large coronary vessels. Kaplan–Meier curve depicting survival free of MACE.
127
f
Prescient Medical, Inc., Doylestown, PA, USA Massachusetts Institute of Technology, Cambridge, MA, USA h Massachusetts General Hospital Pathology Service, Boston, MA, USA g
doi:10.1016/j.carrev.2007.03.114
The residual persistent plaque burden predicts the restenosis of drug-eluting stents T Okabe, AN Buch, A Javaid, DH Steinberg, T Pinto Slottow, P Roy, YJ Hong, KA Smith, R Torguson, N Gevorkian, Z Xue, LF Satler, KM Kent, AD Pichard, R Waksman Washington Hospital Center, Washington, DC, USA Background: We sought to determine whether IVUS parameters were predictive for the restenosis after DES deployment. Method and results: The restenosis group was 51 patients (42 Cypher, 9 Taxus) angiographically determined as the DES restenosis. The control group was 50 matched cases (42 Cypher, 8 Taxus). The area of external elastic membrane (EEM), stent (SA), and lumen (LA) was measured, and plaque+media (P&M) area (=EEM-LA) was calculated. Twenty out of 51 restenosis cases had follow-up IVUS examinations, and the analysis was performed just within 5 mm long distal and proximal to the minimum LA within stents. In-stent neointimal hyperplastic (INH) area was calculated (INH=SA-LA at follow-up). Volume was calculated by using Simpson’s rule. After DES deployment, residual plaque volume and vessel volume at stented segment were significantly larger in the restenosis group with no differences in SV. Multivariate analysis revealed that residual plaque volume around DES after the deployment (odds ratio 1.028, 95% CI 1.001–1.056, P=.0389) could be the significant predictive factor for the restenosis. There was a significant correlation between residual plaque volume around DES after the deployment and INH volume at follow-up within analyzed segments ( Pb.0319, r=0.5409). Conclusion: Residual plaque volume around the stent at the procedure detected by IVUS might be the predictive factor for DES restenosis.
doi:10.1016/j.carrev.2007.03.115
Percutaneous intracoronary Raman spectroscopy JT Motza,b, GJ Puppelsc, S Waxmand,e, TC Bakker Schutc, E Marplef, N Greenf, J Nazemif, AH Chaub,g, JA Gardeckib, JF Brennan III f, GJ Tearneya,b,h a Harvard Medical School, Boston, MA, USA b Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA c River Diagnostics B.V., Rotterdam, Netherlands d Lahey Clinic, Burlington, MA, USA e Tufts University School of Medicine, Boston, MA, USA
Background: Rupture of coronary atherosclerotic plaque with subsequent thrombosis accounts for the majority of acute myocardial infarctions, one of the leading causes of death in the United States. While much remains to be understood about this disease, it is currently recognized that structural, biochemical, and molecular plaque features all play a role in the pathogenesis of plaque rupture. Significant progress has been made developing structural imaging methods to evaluate plaque morphology. At present, however, there are no tools for evaluating coronary chemical or molecular composition in patients. Raman spectroscopy, a method of measuring molecular vibrations, is uniquely capable of assessing atherosclerotic chemistry in situ. Previous Raman studies conducted ex vivo and in the peripheral vasculature in vivo have demonstrated its ability to distinguish different stages of atherogenesis, lesion types, and a variety of important chemical compounds within plaques. Here we present the first demonstration of percutaneous intracoronary Raman spectroscopy. Methods: Raman spectra were collected with a custom-built system which provided real-time data presentation (River Diagnostics BV, Model 2500 HPRM, modified). The excitation laser power was set to 38 mW at 670 nm such that the spectral coverage included the wavenumber region ranging from 2600 to 3100 cm1. All measurements were performed with a 3.2-F side-viewing, single optical fiber, low-pressure eccentric balloon catheter that was built in-house. Inflation of the balloon expanded the catheter to ~7.5 F, provided apposition of the optical fiber to the arterial wall and displaced a majority of the intervening blood. Spectra were collected at 0.2-s intervals for a total of 10 s. A ~45-kg Yorkshire pig was anesthetized and an 8-F guiding catheter was placed in the femoral artery. The Raman catheter was advanced to the left subclavian artery over a guidewire using fluoroscopy to identify the marker band. Spectra were obtained with the balloon inflated and deflated from two different locations. The catheter was then relocated to the proximal right coronary artery (RCA) where spectra were obtained from two locations, approximately 1 mm apart, again with the balloon inflated and deflated and also with and without a nonocclusive saline flush of ~5 ml. In both vessels, multiple spectra were acquired from at least one location to assess repeatability. The procedure was approved by IACUC at Tufts-New England Medical Center where the study was performed. Results: Interpretable Raman spectra were obtained in all cases when averaged over 1 s, and higher quality data were obtained with 10 s averaging. In both vessels there was typically a clear difference in spectra between the inflated and deflated balloon cases, with the latter being dominated by signal from the blood. Spectra obtained with the inflated balloon in the subclavian artery were generally dominated by protein from the arterial wall; however, in some cases signal from the blood was present due to incomplete apposition to the wall caused by a mismatch between the vessel and inflated catheter diameters. All spectra from the inflated balloon in the RCA were dominated by signal from the artery, with little signal from the blood. These spectra were composed of signatures representing a combination of proteins from the wall and fat from the adventitia. Slight second-to-second variations could be observed due to cardiac motion. During the saline purge, signal from the water was present along with the vessel wall spectrum. Conclusion: We have demonstrated the first percutaneous in vivo intracoronary collection of Raman spectra. In addition, the spectra were collected in a blood field by providing gentle apposition to the arterial wall. Minor modifications to the system and catheters will result in several orders of magnitude improvement in signal quality, allowing a significant decrease in sampling time. Future investigations will employ a modified catheter which allows simultaneous sampling of multiple circumferential points of the vessel during a continuous pullback enabling chemical interrogation of the arterial wall at scan rates comparable to IVUS. doi:10.1016/j.carrev.2007.03.116
127
f
Prescient Medical, Inc., Doylestown, PA, USA Massachusetts Institute of Technology, Cambridge, MA, USA h Massachusetts General Hospital Pathology Service, Boston, MA, USA g
doi:10.1016/j.carrev.2007.03.114
The residual persistent plaque burden predicts the restenosis of drug-eluting stents T Okabe, AN Buch, A Javaid, DH Steinberg, T Pinto Slottow, P Roy, YJ Hong, KA Smith, R Torguson, N Gevorkian, Z Xue, LF Satler, KM Kent, AD Pichard, R Waksman Washington Hospital Center, Washington, DC, USA Background: We sought to determine whether IVUS parameters were predictive for the restenosis after DES deployment. Method and results: The restenosis group was 51 patients (42 Cypher, 9 Taxus) angiographically determined as the DES restenosis. The control group was 50 matched cases (42 Cypher, 8 Taxus). The area of external elastic membrane (EEM), stent (SA), and lumen (LA) was measured, and plaque+media (P&M) area (=EEM-LA) was calculated. Twenty out of 51 restenosis cases had follow-up IVUS examinations, and the analysis was performed just within 5 mm long distal and proximal to the minimum LA within stents. In-stent neointimal hyperplastic (INH) area was calculated (INH=SA-LA at follow-up). Volume was calculated by using Simpson’s rule. After DES deployment, residual plaque volume and vessel volume at stented segment were significantly larger in the restenosis group with no differences in SV. Multivariate analysis revealed that residual plaque volume around DES after the deployment (odds ratio 1.028, 95% CI 1.001–1.056, P=.0389) could be the significant predictive factor for the restenosis. There was a significant correlation between residual plaque volume around DES after the deployment and INH volume at follow-up within analyzed segments ( Pb.0319, r=0.5409). Conclusion: Residual plaque volume around the stent at the procedure detected by IVUS might be the predictive factor for DES restenosis.
doi:10.1016/j.carrev.2007.03.115
Percutaneous intracoronary Raman spectroscopy JT Motza,b, GJ Puppelsc, S Waxmand,e, TC Bakker Schutc, E Marplef, N Greenf, J Nazemif, AH Chaub,g, JA Gardeckib, JF Brennan III f, GJ Tearneya,b,h a Harvard Medical School, Boston, MA, USA b Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA c River Diagnostics B.V., Rotterdam, Netherlands d Lahey Clinic, Burlington, MA, USA e Tufts University School of Medicine, Boston, MA, USA
Background: Rupture of coronary atherosclerotic plaque with subsequent thrombosis accounts for the majority of acute myocardial infarctions, one of the leading causes of death in the United States. While much remains to be understood about this disease, it is currently recognized that structural, biochemical, and molecular plaque features all play a role in the pathogenesis of plaque rupture. Significant progress has been made developing structural imaging methods to evaluate plaque morphology. At present, however, there are no tools for evaluating coronary chemical or molecular composition in patients. Raman spectroscopy, a method of measuring molecular vibrations, is uniquely capable of assessing atherosclerotic chemistry in situ. Previous Raman studies conducted ex vivo and in the peripheral vasculature in vivo have demonstrated its ability to distinguish different stages of atherogenesis, lesion types, and a variety of important chemical compounds within plaques. Here we present the first demonstration of percutaneous intracoronary Raman spectroscopy. Methods: Raman spectra were collected with a custom-built system which provided real-time data presentation (River Diagnostics BV, Model 2500 HPRM, modified). The excitation laser power was set to 38 mW at 670 nm such that the spectral coverage included the wavenumber region ranging from 2600 to 3100 cm1. All measurements were performed with a 3.2-F side-viewing, single optical fiber, low-pressure eccentric balloon catheter that was built in-house. Inflation of the balloon expanded the catheter to ~7.5 F, provided apposition of the optical fiber to the arterial wall and displaced a majority of the intervening blood. Spectra were collected at 0.2-s intervals for a total of 10 s. A ~45-kg Yorkshire pig was anesthetized and an 8-F guiding catheter was placed in the femoral artery. The Raman catheter was advanced to the left subclavian artery over a guidewire using fluoroscopy to identify the marker band. Spectra were obtained with the balloon inflated and deflated from two different locations. The catheter was then relocated to the proximal right coronary artery (RCA) where spectra were obtained from two locations, approximately 1 mm apart, again with the balloon inflated and deflated and also with and without a nonocclusive saline flush of ~5 ml. In both vessels, multiple spectra were acquired from at least one location to assess repeatability. The procedure was approved by IACUC at Tufts-New England Medical Center where the study was performed. Results: Interpretable Raman spectra were obtained in all cases when averaged over 1 s, and higher quality data were obtained with 10 s averaging. In both vessels there was typically a clear difference in spectra between the inflated and deflated balloon cases, with the latter being dominated by signal from the blood. Spectra obtained with the inflated balloon in the subclavian artery were generally dominated by protein from the arterial wall; however, in some cases signal from the blood was present due to incomplete apposition to the wall caused by a mismatch between the vessel and inflated catheter diameters. All spectra from the inflated balloon in the RCA were dominated by signal from the artery, with little signal from the blood. These spectra were composed of signatures representing a combination of proteins from the wall and fat from the adventitia. Slight second-to-second variations could be observed due to cardiac motion. During the saline purge, signal from the water was present along with the vessel wall spectrum. Conclusion: We have demonstrated the first percutaneous in vivo intracoronary collection of Raman spectra. In addition, the spectra were collected in a blood field by providing gentle apposition to the arterial wall. Minor modifications to the system and catheters will result in several orders of magnitude improvement in signal quality, allowing a significant decrease in sampling time. Future investigations will employ a modified catheter which allows simultaneous sampling of multiple circumferential points of the vessel during a continuous pullback enabling chemical interrogation of the arterial wall at scan rates comparable to IVUS. doi:10.1016/j.carrev.2007.03.116