Minimaze procedure

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Minimaze procedure
ICD-9-CM 37.33

The mini-maze procedures are cardiac surgery procedures intended to cure atrial fibrillation (AF), a common disturbance of heart rhythm. They are procedures derived from the original maze procedure developed by James Cox, MD.

Contents

The origin of the mini-maze procedures: The Cox maze procedure

James Cox, MD, and associates developed the "maze" or "Cox maze" procedure, an "open-heart" cardiac surgery procedure intended to eliminate atrial fibrillation, and performed the first one in 1987. [1] "Maze" refers to the series of incisions arranged in a maze-like pattern in the atria. The intention was to eliminate AF by using incisional scars to block abnormal electrical circuits (atrial macroreentry) that AF requires. This required an extensive series of endocardial (from the inside of the heart) incisions through both atria, a median sternotomy (vertical incision through the breastbone) and cardiopulmonary bypass (heart-lung machine; extracorporeal circulation). A series of improvements were made, culminating in 1992 in the Cox maze III procedure, originally a cut-and-sew procedure, but later performed with cryosurgical lesions. [2] In 2002 Maze IV was first used combining bipolar radiofrequency clamps with linear cryoprobes. [2] Cox-Maze IV is now considered to be the "gold standard" for effective surgical cure of AF, but the results are institution dependent. [3] It was quite successful in eliminating AF, but had drawbacks as well. [4] The Cox maze III is sometimes referred to as the "Traditional maze", the "cut and sew maze", or simply the "maze".[ citation needed ]

Minimally invasive epicardial surgical procedures for AF (minimaze)

Efforts have since been made to equal the success of the Cox maze III while reducing surgical complexity and likelihood of complications. During the late 1990s, operations similar to the Cox maze, but with fewer atrial incisions, led to the use of the terms "minimaze", "mini maze" and "mini-maze", [5] although these were still major operations.

A primary goal has been to perform a curative, "maze-like" procedure epicardially (from the outside of the heart), so that it could be performed on a normally beating heart, without cardiopulmonary bypass. Until recently this was not thought possible; as recently as 2004, Dr. Cox defined the mini-maze as requiring an endocardial approach:[ citation needed ]

"In summary, it would appear that placing the following lesions can cure most patients with atrial fibrillation of either type: pulmonary vein encircling incision, left atrial isthmus lesion with its attendant coronary sinus lesion, and the right atrial isthmus lesion. We call this pattern of atrial lesions the "mini-maze Procedure" ... None of the present energy sources—including cryotherapy, unipolar radiofrequency, irrigated radiofrequency, bipolar radiofrequency, microwave, and laser energy—are capable of creating the left atrial isthmus lesion from the epicardial surface, because of the necessity of penetrating through the circumflex coronary artery to reach the left atrial wall near the posterior mitral annulus. Therefore, the mini-maze procedure cannot be performed epicardially by means of any presently available energy source." [6]

Although Dr. Cox's 2004 definition specifically excludes an epicardial approach to eliminate AF, he and others pursued this important goal, and the meaning of the term changed as successful epicardial procedures were developed. In 2002 Saltman performed a completely endoscopic surgical ablation of AF [7] and subsequently published their results in 14 patients. [8] These were performed epicardially, on the beating heart, without cardiopulmonary bypass or median sternotomy. Their method came to be known as the minimaze or microwave minimaze procedure, because microwave energy was used to make the lesions that had previously been performed by the surgeon's scalpel.

Shortly thereafter, Randall K. Wolf, MD and others developed a procedure using radiofrequency energy rather than microwave, and different, slightly larger incisions. In 2005, he published his results in the first 27 patients. [9] This came to be known as the Wolf minimaze procedure.[ citation needed ]

Today, the terms "minimaze", "mini-maze", and "mini maze" are still sometimes used to describe open heart procedures requiring cardiopulmonary bypass and median sternotomy, but more commonly they refer to minimally invasive, epicardial procedures not requiring cardiopulmonary bypass, such as those developed by Saltman, Wolf, and others. These procedures are characterized by:

  1. No median sternotomy incision; instead, an endoscope and/or "mini-thoracotomy" incisions between the ribs are used.
  2. No cardiopulmonary bypass; instead, these procedures are performed on the normally beating heart.
  3. Few or no actual incisions into the heart itself. The "maze" lesions are made epicardially by using radiofrequency, microwave, or ultrasonic energy, or by cryosurgery.
  4. The part of the left atrium in which most clots form (the "appendage") is usually removed, in an effort to reduce the long-term likelihood of stroke.

Microwave minimaze

Completely Endoscopic Microwave Ablation of Atrial Fibrillation on the Beating Heart Using Bilateral Thoracoscopy: The microwave minimaze requires three 5 mm to 1 cm incisions on each side of the chest for the surgical tools and the endoscope. The pericardium is entered, and two sterile rubber tubes are threaded behind the heart, in the transverse and oblique sinuses. These tubes are joined, then used to guide the flexible microwave antenna energy source through the sinuses behind the heart, to position it for ablation. Energy is delivered and the atrial tissue heated and destroyed in a series of steps as the microwave antenna is withdrawn behind the heart. The lesions form a "box-like" pattern around all four pulmonary veins behind the heart. The left atrial appendage is usually removed. [7] [8]

Wolf minimaze

Video-assisted Bilateral Epicardial Bipolar Radiofrequency Pulmonary Vein Isolation and Left Atrial Appendage Excision: The Wolf minimaze requires one 5 cm and two 1 cm incisions on each side of the chest. These incisions allow the surgeon to maneuver the tools, view areas through an endoscope, and to see the heart directly. The right side of the left atrium is exposed first. A clamp-like tool is positioned on the left atrium near the right pulmonary veins, and the atrial tissue is heated between the jaws of the clamp, cauterizing the area. The clamp is removed. The autonomic nerves (ganglionated plexi) that may cause AF [10] may be eliminated as well. Subsequently, the left side of the chest is entered. The ligament of Marshall (a vestigial structure with marked autonomic activity) is removed. The clamp is subsequently positioned on the left atrium near the left pulmonary veins for ablation. Direct testing to demonstrate complete electrical isolation of the pulmonary veins, and that the ganglionated plexi are no longer active, may be performed. [9]

High Intensity Focused Ultrasound (HIFU) minimaze

Surgical ablation of atrial fibrillation with off-pump, epicardial, high-intensity focused ultrasound: Although the HIFU minimaze is performed epicardially, on the normally beating heart, it is also usually performed in conjunction with other cardiac surgery, and so would not be minimally invasive in those cases. An ultrasonic device is positioned epicardially, on the left atrium, around the pulmonary veins, and intense acoustic energy is directed at the atrium to destroy tissue in the appropriate regions near the pulmonary veins. [11]

Mechanism of elimination of atrial fibrillation

The mechanism by which AF is eliminated by curative procedures such as the maze, minimaze, or catheter ablation is controversial. All successful methods destroy tissue in the areas of the left atrium near the junction of the pulmonary veins, hence these regions are thought to be important. A concept gaining support is that paroxysmal AF is mediated in part by the autonomic nervous system [10] and that the intrinsic cardiac nervous system, which is located in these regions, plays an important role. [12] Supporting this is the finding that targeting these autonomic sites improves the likelihood of successful elimination of AF by catheter ablation. [13] [14]

Patient selection

The minimaze procedures are alternatives to catheter ablation of AF, and the patient selection criteria are similar. Patients are considered for minimaze procedures if they have moderate or severe symptoms and have failed medical therapy; asymptomatic patients are generally not considered. Those most likely to have a good outcome have paroxysmal (intermittent) AF, and have a heart that is relatively normal. Those with severely enlarged atria, [15] marked cardiomyopathy, or severely leaking heart valves are less likely to have a successful result; these procedures are generally not recommended for such patients. Previous cardiac surgery provides technical challenges due to scarring on the outside of the heart, but does not always preclude minimaze surgery.[ citation needed ]

Surgical results

A 2013 review found the results of the minimally-invasive mini-maze procedure to be intermediate between the standard maze procedure and catheter ablation. [16]

Long-term success of the minimaze procedures awaits a consensus. Attaining a consensus is hindered by several problems; perhaps the most important of these is incomplete or inconsistent post-procedure follow-up to determine if atrial fibrillation has recurred, although many reasons have been considered. [17] It has been clearly demonstrated that longer or more intensive follow-up identifies much more recurrent atrial fibrillation, [18] hence a procedure with more careful follow-up will appear to be less successful. In addition, procedures continue to evolve rapidly, so long follow-up data do not accurately reflect current procedural methods. For more recent minimaze procedures, only relatively small and preliminary reports are available. With those caveats in mind, it can be said that reported short-term freedom from atrial fibrillation following the radiofrequency ("Wolf") procedure ranges from 67% to 91% [8] [9] [11] with longer-term results in a similar range, but limited primarily to patients with paroxysmal atrial fibrillation. [19] [20]

Related Research Articles

<span class="mw-page-title-main">Pulmonary vein</span> Veins that transfer oxygenated blood from the lungs to the heart

The pulmonary veins are the veins that transfer oxygenated blood from the lungs to the heart. The largest pulmonary veins are the four main pulmonary veins, two from each lung that drain into the left atrium of the heart. The pulmonary veins are part of the pulmonary circulation.

<span class="mw-page-title-main">Catheter ablation</span> Removal or termination of an electrical pathway from parts of the heart

Catheter ablation is a procedure that uses radio-frequency energy or other sources to terminate or modify a faulty electrical pathway from sections of the heart of those who are prone to developing cardiac arrhythmias such as atrial fibrillation, atrial flutter and Wolff-Parkinson-White syndrome. If not controlled, such arrhythmias increase the risk of ventricular fibrillation and sudden cardiac arrest. The ablation procedure can be classified by energy source: radiofrequency ablation and cryoablation.

<span class="mw-page-title-main">Radiofrequency ablation</span> Surgical procedure

Radiofrequency ablation (RFA), also called fulguration, is a medical procedure in which part of the electrical conduction system of the heart, tumor or other dysfunctional tissue is ablated using the heat generated from medium frequency alternating current. RFA is generally conducted in the outpatient setting, using either local anesthetics or twilight anesthesia. When it is delivered via catheter, it is called radiofrequency catheter ablation.

<span class="mw-page-title-main">Aortic valve repair</span> Treatment of aortic regurgitation

Aortic valve repair or aortic valve reconstruction is the reconstruction of both form and function of a dysfunctional aortic valve. Most frequently it is used for the treatment of aortic regurgitation. It can also become necessary for the treatment of aortic aneurysm, less frequently for congenital aortic stenosis.

Cor triatriatum is a congenital heart defect where the left atrium or right atrium is subdivided by a thin membrane, resulting in three atrial chambers.

<span class="mw-page-title-main">Arterial switch operation</span> Open heart surgical procedure

Arterial switch operation (ASO) or arterial switch, is an open heart surgical procedure used to correct dextro-transposition of the great arteries (d-TGA).

The Dor procedure is a medical technique used as part of heart surgery and originally introduced by the French cardiac surgeon Vincent Dor (b.1932). It is also known as endoventricular circular patch plasty (EVCPP).

The Kawashima procedure is used for congenital heart disease with a single effective ventricle and an interrupted inferior vena cava (IVC). It was first performed in 1978 and reported in 1984.

The Cox maze procedure, also known as maze procedure, is a type of heart surgery for atrial fibrillation.

<span class="mw-page-title-main">Video-assisted thoracoscopic surgery</span>

Video-assisted thoracoscopic surgery (VATS) is a type of minimally invasive thoracic surgery performed using a small video camera mounted to a fiberoptic thoracoscope, with or without angulated visualization, which allows the surgeon to see inside the chest by viewing the video images relayed onto a television screen, and perform procedures using elongated surgical instruments. The camera and instruments are inserted into the patient's chest cavity through small incisions in the chest wall, usually via specially designed guiding tubes known as "ports".

The Sensei X robotic catheter is a medical robot designed to enhance a physician’s ability to perform complex operations using a small flexible tube called a catheter. As open surgical procedures that require large incisions have given way to minimally invasive surgeries in which the surgeon gains access to the target organs through small incisions using specialized surgical tools. One important tool used in many of these procedures is a catheter used to deliver many of things a surgeon needs to do his work, to impact target tissue and deliver a variety of medicines or disinfecting agents to treat disease or infection.

<span class="mw-page-title-main">Atrial fibrillation</span> Irregular beating of the atria of the heart

Atrial fibrillation is an abnormal heart rhythm (arrhythmia) characterized by rapid and irregular beating of the atrial chambers of the heart. It often begins as short periods of abnormal beating, which become longer or continuous over time. It may also start as other forms of arrhythmia such as atrial flutter that then transform into AF.

<span class="mw-page-title-main">Anomalous pulmonary venous connection</span> Medical condition

Anomalous pulmonary venous connection is a congenital heart defect of the pulmonary veins. It can be a total anomalous pulmonary venous connection, wherein all four pulmonary veins are incorrectly positioned, or a partial anomalous pulmonary venous connection, wherein only some of the pulmonary veins are incorrectly positioned.

<span class="mw-page-title-main">Left atrial appendage occlusion</span> Medical treatment

Left atrial appendage occlusion (LAAO), also referred to as left atrial appendage closure (LAAC), is a procedure used to reduce the risk of blood clots from the left atrial appendage entering the bloodstream and causing a stroke in those with non-valvular atrial fibrillation.

The management of atrial fibrillation (AF) is focused on preventing temporary circulatory instability, stroke and other ischemic events. Control of heart rate and rhythm are principally used to achieve the former, while anticoagulation may be employed to decrease the risk of stroke. Within the context of stroke, the discipline may be referred to as stroke prevention in atrial fibrillation (SPAF). In emergencies, when circulatory collapse is imminent due to uncontrolled rapid heart rate, immediate cardioversion may be indicated.

James L. Cox is an American cardiothoracic surgeon and medical innovator best known for the development of the Cox maze procedure for treatment of atrial fibrillation in 1987.

An Af-nest or Atrial Fibrillation Nest (AFN) is a locus or cluster in the atrial wall with distinct electrical features and properties originated by fibrillar myocardium. It plays as an "electrical multiplier" re-feeding the atrial fibrillation.

<span class="mw-page-title-main">Topera Medical</span>

Topera, Inc. is a cardiac arrhythmia mapping company for targeting catheter ablation company launched in San Diego, California and specializes in mapping electrical signals of the heart. Topera's headquarters are located in Palo Alto, California. The company uses 3D analysis and mapping to detect the sources of atrial fibrillation, atrial flutter, and atrial tachycardia and ventricular tachycardia to identify targets for catheter ablation.

<span class="mw-page-title-main">Yaariv Khaykin</span> Canadian cardiologist

Yaariv Khaykin is a Canadian cardiologist and a clinical researcher in the area of electrophysiology. He is the director of the Newmarket Electrophysiology Research Group at the Southlake Regional Health Centre. He has published research into complex ablation and pioneered cardiac ablation methods.

Ganglionated plexi (GP) comprise the intrinsic cardiac autonomic nervous system composed of autonomic ganglia of the heart atrium and ventricles. The GP are embedded in the epicardial fat pads, consisting of only a few neurons or as many as 400 neurons. GP are spatially close to the pulmonary veins, such that pulmonary vein isolation necessarily affects the GP. GP has been shown to be a contributor to atrial fibrillation (AFib), such that ablation of the GP has been a strategy for treatment of AFib. Addition of GP ablation to pulmonary vein isolation has not improved outcomes, but possibly other methods of GP ablation would be more successful. GP ablation alone has been shown to eliminate AFib in approximately three-quarter of AFib patients.

References

  1. ↑ Cox J, Schuessler R, D'Agostino H, Stone C, Chang B, Cain M, Corr P, Boineau J (1991). "The surgical treatment of atrial fibrillation. III. Development of a definitive surgical procedure". J Thorac Cardiovasc Surg. 101 (4): 569–83. doi:10.1016/S0022-5223(19)36684-X. PMID   2008095.
  2. 1 2 Cox JL, Churyla A, McCarthy PM (2018). "When Is a Maze Procedure a Maze Procedure?". Canadian Journal of Cardiology . 34 (11): 1482–1491. doi:10.1016/j.cjca.2018.05.008. PMID   30121148.
  3. ↑ Wolf RK (2021). "Surgical Treatment of Atrial Fibrillation". Methodist DeBakey Cardiovascular Journal. 17 (1): 56–64. doi:10.14797/VNDG5944. PMC   5834122 . PMID   34104322.
  4. ↑ Prasad S, Maniar H, Camillo C, Schuessler R, Boineau J, Sundt T, Cox J, Damiano R (2003). "The Cox maze III procedure for atrial fibrillation: long-term efficacy in patients undergoing lone versus concomitant procedures". J Thorac Cardiovasc Surg. 126 (6): 1822–8. doi: 10.1016/S0022-5223(03)01287-X . PMID   14688693.
  5. ↑ Szalay Z, Skwara W, Pitschner H, Faude I, Klövekorn W, Bauer E (1999). "Midterm results after the mini-maze procedure". Eur J Cardiothorac Surg. 16 (3): 306–11. doi: 10.1016/S1010-7940(99)00208-0 . PMID   10554849.
  6. ↑ Cox J (2004). "The Role of Surgical Intervention in the Management of Atrial Fibrillation". Tex Heart Inst J. 31 (3): 257–65. PMC   521766 . PMID   15562846.
  7. 1 2 Saltman A, Rosenthal L, Francalancia N, Lahey S (2003). "A completely endoscopic approach to microwave ablation for atrial fibrillation". Heart Surg Forum. 6 (3): E38–41. PMID   12821436.
  8. 1 2 3 Salenger R, Lahey S, Saltman A (2004). "The completely endoscopic treatment of atrial fibrillation: report on the first 14 patients with early results". Heart Surg Forum. 7 (6): E555–8. doi:10.1532/HSF98.20041111. PMID   15769685.
  9. 1 2 3 Wolf R, Schneeberger E, Osterday R, Miller D, Merrill W, Flege J, Gillinov A (2005). "Video-assisted bilateral pulmonary vein isolation and left atrial appendage exclusion for atrial fibrillation". J Thorac Cardiovasc Surg. 130 (3): 797–802. doi: 10.1016/j.jtcvs.2005.03.041 . PMID   16153931.
  10. 1 2 Coumel P (1994). "Paroxysmal atrial fibrillation: a disorder of autonomic tone?". Eur Heart J. 15 Suppl A: 9–16. doi:10.1093/eurheartj/15.suppl_a.9. PMID   8070496.
  11. 1 2 Ninet J, Roques X, Seitelberger R, Deville C, Pomar J, Robin J, Jegaden O, Wellens F, Wolner E, Vedrinne C, Gottardi R, Orrit J, Billes M, Hoffmann D, Cox J, Champsaur G (2005). "Surgical ablation of atrial fibrillation with off-pump, epicardial, high-intensity focused ultrasound: results of a multicenter trial". J Thorac Cardiovasc Surg. 130 (3): 803–9. doi: 10.1016/j.jtcvs.2005.05.014 . PMID   16153932.
  12. ↑ Scherlag B, Po S (2006). "The intrinsic cardiac nervous system and atrial fibrillation". Current Opinion in Cardiology. 21 (1): 51–4. doi:10.1097/01.hco.0000198980.40390.e4. PMID   16355030. S2CID   34469546.
  13. ↑ Pappone C, Santinelli V, Manguso F, Vicedomini G, Gugliotta F, Augello G, Mazzone P, Tortoriello V, Landoni G, Zangrillo A, Lang C, Tomita T, Mesas C, Mastella E, Alfieri O (2004). "Pulmonary vein denervation enhances long-term benefit after circumferential ablation for paroxysmal atrial fibrillation". Circulation. 109 (3): 327–34. doi: 10.1161/01.CIR.0000112641.16340.C7 . PMID   14707026.
  14. ↑ Scherlag B, Nakagawa H, Jackman W, Yamanashi W, Patterson E, Po S, Lazzara R (2005). "Electrical stimulation to identify neural elements on the heart: their role in atrial fibrillation". J Interv Card Electrophysiol. 13 (Suppl 1): 37–42. doi:10.1007/s10840-005-2492-2. PMID   16133854. S2CID   19856445.
  15. ↑ Sunderland, N., Maruthappu, M. & Nagendran, M. (2011). "What size of left atrium significantly impairs the success of maze surgery for atrial fibrillation?". Interact Cardiovasc Thorac Surg. 13 (3): 332–8. doi: 10.1510/icvts.2011.271999 . PMID   21632865.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  16. ↑ Krul SP, Driessen AH, de Groot JR (2013). "Navigating the mini-maze: systematic review of the first results and progress of minimally-invasive surgery in the treatment of atrial fibrillation". International Journal of Cardiology . 168 (1): 132–140. doi:10.1016/j.ijcard.2011.10.011. PMID   22078990.
  17. ↑ Calkins H, Brugada J, Packer DL, Cappato R, Chen SA, Crijns HJ, Damiano RJ Jr, Davies DW, Haines DE, Haissaguerre M, Iesaka Y, Jackman W, Jais P, Kottkamp H, Kuck KH, Lindsay BD, Marchlinski FE, McCarthy PM, Mont JL, Morady F, Nademanee K, Natale A, Pappone C, Prystowsky E, Raviele A, Ruskin JN, Shemin RJ (2007). "HRS/EHRA/ECAS expert Consensus Statement on catheter and surgical ablation of atrial fibrillation: recommendations for personnel, policy, procedures and follow-up. A report of the Heart Rhythm Society (HRS) Task Force on catheter and surgical ablation of atrial fibrillation". Heart Rhythm. 4 (6): 816–61. doi:10.1016/j.hrthm.2007.04.005. PMID   17556213.
  18. ↑ Israel C, Grönefeld G, Ehrlich J, Li Y, Hohnloser S (2004). "Long-term risk of recurrent atrial fibrillation as documented by an implantable monitoring device: implications for optimal patient care". J Am Coll Cardiol. 43 (1): 47–52. doi: 10.1016/j.jacc.2003.08.027 . PMID   14715182.
  19. ↑ McClelland JH, Duke D, Reddy R (2007). "Preliminary results of a limited thoracotomy: new approach to treat atrial fibrillation". J Cardiovasc Electrophysiol. 18 (12): 1296–8. doi:10.1111/j.1540-8167.2007.00977.x. PMID   17919294. S2CID   13944757.
  20. ↑ Wudel JH, Chaudhuri P, Hiller JJ (2008). "Video-assisted epicardial ablation and left atrial appendage exclusion for atrial fibrillation: extended follow-up". Ann Thorac Surg. 85 (1): 34–8. doi:10.1016/j.athoracsur.2007.08.014. PMID   18154774.
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