Basic principles of rotablation

Basic principles of rotablation

Rotablation or rotational atherectomy uses a diamond coated burr to debulk complex atherosclerotic plaques which are difficult to treat with conventional balloon angioplasty. The physical principle of rotablation is differential cutting. The advancing rotablator burr selectively cuts inelastic material while elastic tissue deflects away from the burr. As 95% of the particles generated by rotablation are less than 5 microns in diameter, they are removed from the body by the reticuloendothelial system [1]. Thus the basic principle of rotablation is quite different from balloon dilatation in which there is displacement of atherosclerotic plaque with multiple tears [2].

Though it was initially used as a debulking strategy, later the emphasis was on plaque modification prior to stent implantation. Rotablation facilitates percutaneous coronary intervention (PCI) for de novo complex lesions with severe calcification. Burr to artery ratio of 0.5 to 0.6 and rotational speed of 140,000 to 150,000 rpm have been suggested. The burr should be advanced gradually with a pecking motion (quick push forward/pull back movement of the burr). Short ablation runs of 15 to 20 seconds and avoidance of decelerations more than 5,000 rpm are also suggested. Other adjunctive measures are the use of antiplatelet agents, vasodilators, flush solutions, and temporary pacing, vasopressors and mechanical support when needed [3]. Due to changes in conceptual understanding of the basic principles of rotablation, the tendency to use it has come down from the 20% in mid 1990s to 1-3% a quarter century after the introduction of the device [2,3]. 

There are advantages for using intravascular ultrasound (IVUS) and optical coherence tomography (OCT) to guide rotational atherectomy. IVUS is useful to understand guidewire bias and to decide on appropriate size of burr for the procedure. OCT gives an idea about the thickness of the calcification in the lesion [4].

Good lesion preparation by rotablation prior to the delivery of stent can be useful in avoiding damage to polymer of the drug eluting stent in calcified lesions [5]. Bradycardia or atrioventricular block may occur during rotablation, especially in case of right coronary artery and need temporary pacing. Short ablation times can reduce the risk of sustained arrhythmia. Risk of ventricular perforation with temporary pacing lead has to be borne in mind while inserting the lead [4]. Cough resuscitation may be useful in an emergency to combat transient bradycardia [6].

The system should not be deactivated when the burr is in the middle of stenosis. Deactivation when the burr is in the middle of the stenosis can result in entrapment of the burr. The system should be deactivated after the burr is pulled back into the platform [4].

Rotablator burr sizes range from 1.25-2.5 mm and burr speeds range from 140,000-190,000 rpm. RotaWire guidewires have 0.009″/0.014″ tip. Compressed air or nitrogen is used to spin the drive shaft and the burr. It is pumped through a pneumatic hose into the advancer to rotate the turbine housed within it [7].

References

1. Dill T, Hamm CW. Rotablation: Technik, Indikation, Ergebnisse [Rotational atherectomy: technique, indications, results]. Herz. 1997 Dec;22(6):291-8. 
2. Stankovic G, Milasinovic D. Rotational Atherectomy in Clinical Practice: The Art of Tightrope Walking. Circ Cardiovasc Interv. 2016 Nov;9(11):e004571. 
3. Tomey MI, Kini AS, Sharma SK. Current status of rotational atherectomy. JACC Cardiovasc Interv. 2014 Apr;7(4):345-53. 
4. Sakakura K, Ito Y, Shibata Y, Okamura A, Kashima Y, Nakamura S, Hamazaki Y, Ako J, Yokoi H, Kobayashi Y, Ikari Y. Clinical expert consensus document on rotational atherectomy from the Japanese association of cardiovascular intervention and therapeutics. Cardiovasc Interv Ther. 2021 Jan;36(1):1-18. 
5. Kuriyama N, Kobayashi Y, Yamaguchi M, Shibata Y. Usefulness of rotational atherectomy in preventing polymer damage of everolimus-eluting stent in calcified coronary artery. JACC Cardiovasc Interv. 2011 May;4(5):588-9. 
6. LoMauro A, Aliverti A. Blood Shift During Cough: Negligible or Significant? Front Physiol. 2018 May 28;9:501.
7. Gupta T, Weinreich M, Greenberg M, Colombo A, Latib A. Rotational Atherectomy: A Contemporary Appraisal. Interv Cardiol. 2019 Nov 18;14(3):182-189.