Abstract
OBJECTIVES: Atrial fibrillation is treated surgically by creating conduction block lesions. Radiofrequency (RF) lesions have reduced efficacy compared to 'cut-and-sew'. Catheter ablation studies demonstrate a relationship between lesion depth and contact force. We hypothesized that contact force and lesion depth are dependent on design of the bipolar surgical RF clamps. METHODS: Hinged and parallel jaw style RF clamps were studied. Muscle samples were clamped with pressure-sensitive film at increasing tissue thicknesses. Films were analysed determining clamp pressure profiles. A sheep model was utilized for ablation testing using each clamp style until the device indicated transmurality. Separate muscle areas had 1, 2 or 3 burns applied. The muscle was excised, sectioned every 1 cm and stained for lesion depth and fat thickness analysis. RESULTS: Pressure profiling comparing the proximal and distal segments of each clamp style demonstrated only one statistically significant difference in the parallel clamp; the hinged clamp had statistically significant differences (P ≤ 0.03) for all tissue thicknesses. There was no evidence for differences in the proximal lesion depth of both clamps (P = 0.13) but deeper distally in the parallel clamp (10.17 mm vs 8.02 mm, P = 0.003). The logistic regression analysis demonstrated increased odds of transmurality with parallel clamps at 1, 2 or 3 burns (P = 0.03, P = 0.003 and P = 0.002). Every 1 mm increase in overlying fat decreased likelihood of transmurality by 11% (P < 0.05). CONCLUSIONS: The parallel and hinged clamps have different pressure profiles with higher likelihood of transmurality using the parallel clamp. Fat reduces the ability of RF to deliver a transmural lesion. These findings have implications for optimal surgical RF ablation technique.
| Language | English |
|---|---|
| Pages | 85-93 |
| Number of pages | 9 |
| Journal | Interactive cardiovascular and thoracic surgery |
| Volume | 28 |
| Issue number | 1 |
| DOIs | |
| State | Published - 1 Jan 2019 |
ASJC Scopus subject areas
- Surgery
- Pulmonary and Respiratory Medicine
- Cardiology and Cardiovascular Medicine
Cite this
}
Contact force and ablation assessment of surgical bipolar radiofrequency clamps in the treatment of atrial fibrillation. / Varzaly, Jason A.; Chapman, Darius; Lau, Dennis H.; Edwards, Suzanne; Louise, Jennie; Edwards, James; Mahajan, Rajiv; Worthington, Michael; Sanders, Prashanthan.
In: Interactive cardiovascular and thoracic surgery, Vol. 28, No. 1, 01.01.2019, p. 85-93.Research output: Research - peer-review › Article
TY - JOUR
T1 - Contact force and ablation assessment of surgical bipolar radiofrequency clamps in the treatment of atrial fibrillation
AU - Varzaly,Jason A.
AU - Chapman,Darius
AU - Lau,Dennis H.
AU - Edwards,Suzanne
AU - Louise,Jennie
AU - Edwards,James
AU - Mahajan,Rajiv
AU - Worthington,Michael
AU - Sanders,Prashanthan
PY - 2019/1/1
Y1 - 2019/1/1
N2 - OBJECTIVES: Atrial fibrillation is treated surgically by creating conduction block lesions. Radiofrequency (RF) lesions have reduced efficacy compared to 'cut-and-sew'. Catheter ablation studies demonstrate a relationship between lesion depth and contact force. We hypothesized that contact force and lesion depth are dependent on design of the bipolar surgical RF clamps. METHODS: Hinged and parallel jaw style RF clamps were studied. Muscle samples were clamped with pressure-sensitive film at increasing tissue thicknesses. Films were analysed determining clamp pressure profiles. A sheep model was utilized for ablation testing using each clamp style until the device indicated transmurality. Separate muscle areas had 1, 2 or 3 burns applied. The muscle was excised, sectioned every 1 cm and stained for lesion depth and fat thickness analysis. RESULTS: Pressure profiling comparing the proximal and distal segments of each clamp style demonstrated only one statistically significant difference in the parallel clamp; the hinged clamp had statistically significant differences (P ≤ 0.03) for all tissue thicknesses. There was no evidence for differences in the proximal lesion depth of both clamps (P = 0.13) but deeper distally in the parallel clamp (10.17 mm vs 8.02 mm, P = 0.003). The logistic regression analysis demonstrated increased odds of transmurality with parallel clamps at 1, 2 or 3 burns (P = 0.03, P = 0.003 and P = 0.002). Every 1 mm increase in overlying fat decreased likelihood of transmurality by 11% (P < 0.05). CONCLUSIONS: The parallel and hinged clamps have different pressure profiles with higher likelihood of transmurality using the parallel clamp. Fat reduces the ability of RF to deliver a transmural lesion. These findings have implications for optimal surgical RF ablation technique.
AB - OBJECTIVES: Atrial fibrillation is treated surgically by creating conduction block lesions. Radiofrequency (RF) lesions have reduced efficacy compared to 'cut-and-sew'. Catheter ablation studies demonstrate a relationship between lesion depth and contact force. We hypothesized that contact force and lesion depth are dependent on design of the bipolar surgical RF clamps. METHODS: Hinged and parallel jaw style RF clamps were studied. Muscle samples were clamped with pressure-sensitive film at increasing tissue thicknesses. Films were analysed determining clamp pressure profiles. A sheep model was utilized for ablation testing using each clamp style until the device indicated transmurality. Separate muscle areas had 1, 2 or 3 burns applied. The muscle was excised, sectioned every 1 cm and stained for lesion depth and fat thickness analysis. RESULTS: Pressure profiling comparing the proximal and distal segments of each clamp style demonstrated only one statistically significant difference in the parallel clamp; the hinged clamp had statistically significant differences (P ≤ 0.03) for all tissue thicknesses. There was no evidence for differences in the proximal lesion depth of both clamps (P = 0.13) but deeper distally in the parallel clamp (10.17 mm vs 8.02 mm, P = 0.003). The logistic regression analysis demonstrated increased odds of transmurality with parallel clamps at 1, 2 or 3 burns (P = 0.03, P = 0.003 and P = 0.002). Every 1 mm increase in overlying fat decreased likelihood of transmurality by 11% (P < 0.05). CONCLUSIONS: The parallel and hinged clamps have different pressure profiles with higher likelihood of transmurality using the parallel clamp. Fat reduces the ability of RF to deliver a transmural lesion. These findings have implications for optimal surgical RF ablation technique.
UR - http://www.scopus.com/inward/record.url?scp=85058909797&partnerID=8YFLogxK
U2 - 10.1093/icvts/ivy191
DO - 10.1093/icvts/ivy191
M3 - Article
VL - 28
SP - 85
EP - 93
JO - Interactive Cardiovascular and Thoracic Surgery
T2 - Interactive Cardiovascular and Thoracic Surgery
JF - Interactive Cardiovascular and Thoracic Surgery
SN - 1569-9293
IS - 1
ER -